Batteries and battery packs

Abstract

The present invention relates to the field of battery technology, and discloses a battery and a battery pack, including: a shell, at least one end of which is open; a cover plate, which is arranged corresponding to the opening to block the opening, the shell and the cover plate are enclosed to form a storage space, the cover plate is welded to the shell to form a connecting section weld and a bursting section weld, the connecting section weld and the bursting section weld are connected end to end along the circumference of the cover plate; the fusion depth of the connecting section weld is greater than the fusion depth of the bursting section weld, and / or, the fusion width of the connecting section weld is greater than the fusion width of the bursting section weld; a pole group is arranged in the storage space. In the present invention, when the battery is out of control, the cover plate can explode in the bursting section weld area, thereby quickly tearing the entire bursting section weld, and at the same time, the cover plate and the shell are kept connected at the connecting section weld, so that the cover plate can be completely flipped open, increasing the exhaust port area of ​​the battery, effectively alleviating battery out of control, and improving the safety of battery use.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to batteries and battery packs. Background Art

[0002] The battery generally includes an internal structure and an external structure. The internal structure mainly includes the electrode group, and the external structure mainly includes the cover plate and the shell. The shell provides a space for the electrode group, and the cover plate and the shell are welded together 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, so that when the internal chemical reaction of the battery is out of control and the gas production intensifies, the explosion-proof valve will be broken after reaching a certain pressure, releasing energy and alleviating the battery out of control. However, due to the limited size of the cover plate and the thin explosion-proof valve that is easily affected by mechanics and thermodynamics, the size and layout space of the explosion-proof valve are limited. When the battery is out of control, the exhaust port area of ​​the battery is limited, and the battery out of control mitigation is poor. Summary of the invention

[0003] In view of this, the present invention provides a battery and a battery pack to solve the problem in the prior art that when the battery loses control, the battery exhaust port area is limited and the battery loss control mitigation is poor.

[0004] In a first aspect, the present invention provides a battery, comprising: a shell, at least one end of which is open; a cover plate, arranged corresponding to the opening to seal the opening, the shell and the cover plate enclosed to form a accommodating space, the cover plate is welded to the shell to form a connecting section weld and a bursting section weld, the connecting section weld and the bursting section weld are connected end to end along the circumference of the cover plate; the fusion depth of the connecting section weld is greater than the fusion depth of the bursting section weld, and / or the fusion width of the connecting section weld is greater than the fusion width of the bursting section weld; a pole group, arranged in the accommodating space.

[0005] Beneficial effect: When the battery is out of control, the cover can explode in the blasting section weld area, thereby quickly tearing the entire blasting section weld. At the same time, the cover and the shell are kept connected in the connecting section weld, so that the cover can be completely flipped open, increasing the exhaust port area of ​​the battery, effectively alleviating battery out of control, and improving battery safety.

[0006] In an optional embodiment, the connecting section weld is arranged corresponding to a 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, satisfying L / 2≤Y≤L-20, and the units of Y and L are both mm.

[0007] Beneficial effect: By limiting the length of the weld of the connecting section, the weld of the cover plate can be quickly torn in the blasting section, and the cover plate can be completely opened.

[0008] In an optional embodiment, the molten width of the connecting section weld is w1, and the molten width of the blasting section weld is w2, satisfying 1.2×w2≤w1≤1.5×w2; and / or, the molten depth of the connecting section weld is h1, and the molten depth of the blasting section weld is h2, satisfying 1.2×h2≤h1≤1.5×h2.

[0009] Beneficial effect: While ensuring that the welding strength of the connecting section weld is greater than that of the blasting section weld, it avoids excessive weld width and / or weld depth that may cause defects in the cover plate and the shell.

[0010] In an optional embodiment, the weld width w1 of the connecting section weld satisfies w1≥0.8mm; and / or, the weld depth h1 of the connecting section weld satisfies 0.8mm≤h1≤1mm; and / or, the weld width w2 of the blasting section weld satisfies 0.5mm≤w2≤0.7mm; and / or, the weld depth h2 of the blasting section weld satisfies 0.5mm≤h2≤0.7mm.

[0011] Beneficial effects: While ensuring the welding strength of the connecting section weld, it prevents the molten beads produced by welding from dripping into the battery due to excessive penetration and causing battery failure; while ensuring the welding strength of the blasting section weld, the stability of the cover plate pressed down in the battery is improved, and it is ensured that the cover plate can explode in the blasting section weld area when the battery is out of control.

[0012] In an optional embodiment, the inner wall surface of the shell includes an embedding section, a shielding section and a pole group accommodating section, the four corners of the cover plate are interference fit with the embedding section, and the rest of the cover plate is clearance fit with the embedding section, the depth of the embedding section is d, and the thickness of the cover plate is L2, satisfying L2-0.5≤d≤L2+0.5, L2≥0.5mm, and the units of d and L2 are both mm.

[0013] Beneficial effect: the side of the cover plate away from the accommodating space will neither be too high above the end face of the shell nor too deep into the shell, thereby ensuring good welding quality, and is less likely to have problems such as blowout holes and cold welds, and has high welding strength and welding yield rate; at the same time, the thickness of the cover plate is limited, so that sufficient melting depth can be achieved during welding, and molten beads are less likely to be generated, further ensuring welding quality, and preventing molten beads from falling on the electrode group and burning the electrode group.

[0014] In an optional embodiment, 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, and a first seam is provided between the embedded section and the cover plate, the width of the first seam is b, and 2b≤c≤0.5mm, 0≤b≤0.2mm is satisfied; and / or,

[0015] Two adjacent side plates of the shell are connected by an inner fillet transition, the radius of the inner fillet is R1, and two adjacent side edges of the cover plate are connected by an outer fillet transition, the radius of the outer fillet is R2, and 1.5mm≤R1≤5mm, 0≤R1-R2≤0.5mm is satisfied; and / or,

[0016] The wall thickness of the inlay section is a, which satisfies 0.3 mm ≤ a ≤ 1 mm.

[0017] Beneficial effect: 2b≤c≤0.5mm, so as to prevent the cover plate from being biased to one side during assembly, causing the laser to leak in from the first joint and cause burns to the electrode group;

[0018] 0≤R1-R2≤0.5mm. When the cover plate and the shell are assembled, the cover plate is located in the middle of the shell opening, that is, the sizes of the two first seams are close to each other, so as to prevent the first seam on one side from being too large, thereby preventing the laser from leaking into the electrode group during welding and burning the electrode group.

[0019] Making 0.3mm≤a≤1mm is beneficial to reducing the weight of the shell and saving materials, while ensuring sufficient weld width during welding to ensure welding quality.

[0020] In an optional embodiment, the shell includes two first side panels arranged opposite to each other and two second side panels arranged opposite to each other, the first side panels are connected to the second side panels in sequence, and the two first side panels and the two second side panels are located on the same side The end portions are arranged around the opening, and the cover plate includes a first side edge and a second side edge, a first seam is provided between the first side panel and the first side edge, a second seam is provided between the second side panel and the second side edge, and a width of the second seam is g, satisfying 0≤g≤0.5mm.

[0021] Beneficial effect: When the cover plate and the shell are welded, the second side edge of the cover plate and the second side plate of the shell can be clamped by a clamping tool to return the second joint to zero, thereby preventing the laser from leaking into and burning the electrode group during welding.

[0022] In an optional embodiment, the cover plate is provided with a boss on a 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, satisfying 0.7mm≤L1≤5mm, L3≥0.2mm.

[0023] Beneficial effects: It avoids the total thickness of the cover plate and the boss being too large, which results in excessive material and weight, and it also avoids the total thickness of the cover plate and the boss being too small, which results in low structural strength, and ensures the guiding effect of the boss.

[0024] In an optional embodiment, the guide portion is a chamfered surface that cooperates with the step surface, and an angle x is formed between the step surface and the extended surface of the splicing section. The cover plate includes an outer end surface and a side surface, and the side surface is located in the circumference of the outer end surface and connected to the outer end surface. The side surface cooperates with the splicing section, and an angle z is formed between the chamfered surface and the extended surface of the side surface, and the angle z is greater than or equal to the angle x, and satisfies x≥30° and z≤60°.

[0025] Beneficial effect: When x ≥ 30°, it is helpful to shield the laser from entering, and the step surface of the shielding section can fully abut against the boss, thus supporting the boss and improving the overall stability of the cover plate formed by the cover plate and the boss;

[0026] By making z≤60°, interference between the boss and the shielding section of the shell is avoided, and the chamfered surface can play a good guiding role when the cover plate is assembled into the shell.

[0027] In a second aspect, the present invention further provides a battery pack, comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the exploded structure of a battery according to an embodiment of the present invention;

[0030] Figure 2 A top view of a battery according to an embodiment of the present invention;

[0031] Figure 3 for Figure 2 Sectional view in the AA direction;

[0032] Figure 4 for Figure 3 Cross-sectional view in the BB direction;

[0033] Figure 5 for Figure 3 A partial schematic diagram of point D in the middle (the weld is not shown);

[0034] Figure 6 for Figure 5 a dimensioned schematic diagram of the structure shown;

[0035] Figure 7 for Figure 2 The local schematic diagram of the C in the middle;

[0036] Figure 8 for Figure 4 Partial schematic diagram at point E in the middle.

[0037] Description of reference numerals:

[0038] 1. Shell; 11. Embossed 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. Blasting section weld; 5. Pole group; 6. First joint; 7. Second joint; 8. Boss; 81. Guide portion. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0040] Combine the following Figures 1 to 8 , describing an embodiment of the present invention.

[0041] According to an embodiment of the present invention, on the one hand, a battery is provided, comprising: a shell 1, at least one end of which is open; a cover plate 2, which is arranged corresponding to the opening to block the opening, the shell 1 and the cover plate 2 are enclosed to form a receiving space, the cover plate 2 is welded to the shell 1 to form a connecting section weld 3 and a bursting section weld 4, and the connecting section weld 3 and the bursting section weld 4 are connected end to end 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 fusion width of the connecting section weld 3 is greater than the fusion width of the bursting section weld 4. The electrode group 5 is arranged in the receiving space.

[0042] When the battery is out of control, the cover 2 can explode in the area of ​​the blasting section weld 4, thereby quickly tearing the entire blasting section weld 4. At the same time, the cover 2 and the shell 1 remain connected at the connecting section weld 3, so that the cover 2 can be completely flipped open, increasing the exhaust port area of ​​the battery, effectively alleviating battery out of control, and improving the safety of battery use.

[0043] It is worth noting that in the related art, a notch for the explosion-proof valve is formed on the explosion-proof valve substrate, a hole is opened on the cover plate 2 to form a mounting hole for the explosion-proof valve, and the explosion-proof valve is welded and set corresponding to the mounting hole for the explosion-proof valve. When the battery is out of control, the gas inside the battery reaches the explosion-proof valve through the mounting hole for the explosion-proof valve, and the explosion-proof valve is punched open at the notch for the explosion-proof valve to exhaust the battery. 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 will also increase the time consumption.

[0044] In the present embodiment, the cover plate 2 is welded to the shell 1 by means of the connecting section weld 3 and the bursting section weld 4, so that when the battery is out of control, the cover plate 2 can be completely opened to achieve internal exhaust of the battery, that is, the opening of the shell 1 can be used as an exhaust port, which greatly increases the area of ​​the exhaust port and improves the effect of mitigating thermal runaway; and, there is no need to additionally set up an explosion-proof valve, which achieves savings in production processes and material costs, thereby greatly reducing production costs.

[0045] It should be noted that when the cover plate 2 is opened by the gas pressure inside the battery, the cover plate 2 first explodes at the explosion section weld 4, and then quickly tears the entire explosion section weld 4, and the connecting section weld 3 plays a role in connecting the materials (similar to the principle of a can). Experiments have shown that if there is no connecting section weld 3, the cover plate 2 has a chance of exploding 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 fully opened and the exhaust effect is not obvious.

[0046] It is worth noting that the penetration depth of the connecting section weld 3 is greater than the penetration depth of the blasting section weld 4, and / or the molten width of the connecting section weld 3 is greater than the molten width of the blasting section weld 4, thereby making the welding strength of the connecting section weld 3 greater than the welding strength of the blasting section weld 4.

[0047] In one embodiment, Figure 2 As shown, the connection section weld 3 is arranged corresponding to a side edge of the cover plate 2, the length of the connection section weld 3 is Y, the length of the side edge of the cover plate 2 where the connection section weld 3 is located is L, and L / 2≤Y≤L-20 is satisfied, and the units of Y and L are both mm. By limiting the length of the connection section weld 3, it is convenient for the cover plate 2 to be quickly torn at the blasting section weld 4, and it is ensured that the cover plate 2 can be completely opened.

[0048] It is worth noting that if the length Y of the connecting section weld 3 is too small, the connecting material effect of the connecting section weld 3 is not obvious, which will still cause the cover plate 2 to explode 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 flipped over; if the length Y of the connecting section weld 3 is too large, the bonding force at the transition connection between the side of the cover plate 2 where the connecting section weld 3 is located and the adjacent side is too strong, resulting in the cover plate 2 being more difficult to flip over.

[0049] Please note that Figure 2 The cover plate 2 is usually rectangular in structure, so the complete weld composed of the connecting section weld 3 and the blasting section weld 4 is also rectangular. Figure 2 The connecting section weld 3 is arranged corresponding to one of the long sides of the cover plate 2, that is, for the rectangular weld, there is a connecting section weld 3 on a partial length (length Y) in the middle of one long side, and the rest is the blasting section weld 4.

[0050] In one embodiment, Figure 8 As shown, the weld width of the connection section weld 3 is w1, and the weld width of the blasting section weld 4 is w2, which satisfies 1.2×w2≤w1≤1.5×w2; the penetration depth of the connection section weld 3 is h1, and the penetration depth of the blasting section weld 4 is h2, which satisfies 1.2×h2≤h1≤1.5×h2. While ensuring that the welding strength of the connection section weld 3 is greater than that of the blasting section weld 4, it is avoided that the weld width and / or penetration depth are too large to cause the cover plate 2 and the shell 1 to be defective.

[0051] In one embodiment, Figure 8 As shown, the weld width of the connecting section weld 3 is w1, which satisfies w1≥0.8mm; the weld depth of the connecting section weld 3 is h1, which satisfies 0.8mm≤h1≤1mm. While ensuring the welding strength of the connecting section weld 3, it is prevented that the weld beads generated by the welding drip into the battery interior and burn the electrode group 5 due to excessive weld depth.

[0052] In one embodiment, Figure 8 As shown, the molten width of the blasting section weld 4 is w2, which satisfies 0.5mm≤w2≤0.7mm; the molten depth of the blasting section weld 4 is h2, which satisfies 0.5mm≤h2≤0.7mm. While ensuring the welding strength of the blasting section weld 4 and improving the stability of the cover plate 2 pressed down in the battery, it is ensured that the cover plate 2 can explode in the blasting section weld 4 area when the battery is out of control.

[0053] It is worth noting that if w2 and h2 are too small, the welding strength between the cover plate 2 and the shell 1 is too low. When the battery vibrates and under the internal pressure of the battery, the cover plate 2 is easy to separate from the shell 1, and the stability and reliability of the cover plate 2 during use cannot be guaranteed; if w2 and h2 are too large, the welding strength between the cover plate 2 and the shell 1 is too high. When the battery is out of control, it cannot explode at the explosion section weld 4, affecting the battery exhaust.

[0054] In order to verify that the matching structure of the shell 1 and the cover plate 2 of this embodiment can better complete the explosion-starting and valve-opening function, the following cover plate 2 explosion test is performed on batteries with explosion section welds 4 of different penetration depths and penetration widths and connecting section welds 3 of different lengths. Specifically, a safety valve-opening pressure test of 0.6±0.2Mpa of an iron-lithium battery is adopted. The test results of the embodiment battery and the comparative example battery are shown in Table 1. It should be noted that the embodiment battery refers to a battery whose penetration depth and penetration width of the explosion section weld 4 and the length of the connecting section weld 3 meet the requirements of this embodiment. Correspondingly, the comparative example battery refers to a battery whose penetration depth, or penetration width, or the length of the connecting section weld 3 of the explosion section weld 4 does not meet the requirements of this embodiment.

[0055] Table 1 Explosion test results of cover plate 2

[0056]

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

[0058] It can be seen from Table 1 that in Examples 1 to 4, 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 74mm≤Y≤128mm. Therefore, the battery cover plates 2 of Examples 1 to 4 can all be opened, and the detonation pressures are all within the range of 0.4Mpa to 0.8Mpa, meeting the requirements.

[0059] It can be seen from Table 1 that in Comparative Example 1, the value of h2 is 0.48 mm, which is not within the range of 0.5 mm ≤ h2 ≤ 0.7 mm required by this embodiment and is less than 0.5 mm. The cover plate 2 of the battery can be opened in the explosion test, but the detonation pressure is lower than 0.4 MPa, which does not meet the requirements.

[0060] It can be seen from Table 1 that in Comparative Example 2, the value of w2 is 0.49 mm, which is not within the range of 0.5 mm ≤ w2 ≤ 0.7 mm required by this embodiment and is less than 0.5 mm. The cover plate 2 of the battery can be opened in the explosion test, but the detonation pressure is lower than 0.4 MPa, which does not meet the requirements.

[0061] It can be seen from Table 1 that in Comparative Example 3, the value of Y is 72 mm, which is not within the range of 74 mm ≤ Y ≤ 128 mm required by this embodiment and is less than 74 mm. The battery cannot be opened according to the predetermined trajectory in the explosion test and does not meet the requirements.

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

[0063] It can be seen from Table 1 that in Examples 5 and 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. Therefore, the battery cover plates 2 of Examples 5 and 6 can all be opened, and the detonation pressures are all within the range of 0.4Mpa to 0.8Mpa, which meets the requirements.

[0064] It can be seen from Table 1 that in Comparative Example 4, the value of h2 is 0.71 mm, which is not within the range of 0.5 mm ≤ h2 ≤ 0.7 mm required by this embodiment and is greater than 0.7 mm. The cover plate 2 of the battery can be opened in the explosion test, but the detonation pressure is higher than 0.8 MPa, which does not meet the requirements.

[0065] It can be seen from Table 1 that in Comparative Example 5, the value of w2 is 0.72 mm, which is not within the range of 0.5 mm ≤ w2 ≤ 0.7 mm required by this embodiment and is greater than 0.7 mm. The cover plate 2 of the battery can be opened in the explosion test, but the detonation pressure is higher than 0.8 MPa, which does not meet the requirements.

[0066] It can be seen from Table 1 that in Comparative Example 6, the value of Y is 142 mm, which is not within the range of 80 mm ≤ Y ≤ 140 mm required by this embodiment and is greater than 140 mm. The battery cannot be opened according to the predetermined trajectory in the explosion test and does not meet the requirements.

[0067] In one embodiment, Figure 5 and Figure 6 As shown, the inner wall surface of the shell 1 includes an inlay section 11, a shielding section 12 and a pole group accommodating section 13. The four corners of the cover plate 2 are interference fit with the inlay section 11, and the rest of the cover plate 2 is clearance fit with the inlay section 11. The depth of the inlay section 11 is d, and the thickness of the cover plate 2 is L2, satisfying L2-0.5≤d≤L2+0.5, L2≥0.5mm, and the units of d and L2 are both mm. Therefore, the side of the cover plate 2 away from the accommodating space will neither be too high above the end surface of the shell 1 nor too deep into the shell 1, thereby ensuring good welding quality, not prone to problems such as hole explosion and cold welding, high welding strength and welding yield, and good welding sealing; at the same time, the thickness of the cover plate 2 is limited, so that there can be sufficient penetration during welding, and it is not easy to produce molten beads, further ensuring welding quality, and preventing molten beads from falling on the pole group 5 and burning the pole group 5.

[0068] It is worth noting that the four corners of the cover plate 2 are interference fit with the embedding 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 accommodating space, thereby facilitating the assembly of the cover plate 2; the shielding section 12 can prevent the laser from leaking into the accommodating space during welding, thereby preventing the pole group 5 from being burned.

[0069] In one embodiment, Figure 5 and Figure 6 As shown, the wall thickness of the pole group accommodating section 13 is f, the shielding section 12 has an inclined step surface, the width of the projection of the step surface on the cover plate 2 along the height direction of the shell 1 is c, and there is a first seam 6 between the embedded section 11 and the cover plate 2, and the width of the first seam 6 is b, which satisfies 2b≤c≤0.5mm and 0≤b≤0.2mm. 2b≤c≤0.5mm is set to prevent the cover plate 2 from being biased to one side during assembly, causing the laser to leak in from the first seam 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 is 0 on one side, and the gap on the other side is 2b, so c≥2b is set to ensure that the laser will not leak in even in extreme cases; 0≤b≤0.2mm is set to facilitate the assembly of the cover plate 2 and the shell 1, while preventing the first seam 6 from being too large, causing the laser to leak into the shell 1 and burn the pole group 5.

[0070] It is worth mentioning that please refer to Figure 5 and Figure 6 , f=a+c. If the value of c is too large, the value of f will be too large, that is, the wall thickness of the pole group accommodating section 13 will be too large, resulting in waste of materials and costs.

[0071] In one embodiment, Figure 7 As shown, the two adjacent side plates of the shell 1 are connected by an inner fillet transition, and the radius of the inner fillet is R1. The two adjacent side edges of the cover plate 2 are connected by an outer fillet transition, and the radius of the outer fillet is R2, which satisfies 1.5mm≤R1≤5mm and 0≤R1-R2≤0.5mm. When 0≤R1-R2≤0.5mm is set, when the cover plate 2 and the shell 1 are assembled, the cover plate 2 is located in the middle of the opening of the shell 1, and the sizes of the two first seams 6 are relatively close, so as to prevent the first seam 6 on one side from being too large, thereby avoiding the easy leakage of laser during welding and burning the electrode group 5; when 1.5mm≤R1≤5mm is set, the problem of the welding track being stuck at the matching point of the inner fillet and the outer fillet when the inner fillet is too small, the welding is not smooth, and then the problem of false welding or broken welding is avoided, and the problem of the waste of the housing space of the shell 1 and the reduction of the battery space utilization rate is avoided when the inner fillet is too large.

[0072] In one embodiment, Figure 5 and Figure 6As shown, the wall thickness of the inlay section 11 is a, which satisfies 0.3 mm ≤ a ≤ 1 mm. 0.3 mm ≤ a ≤ 1 mm is beneficial to reducing the weight of the housing 1 and saving materials, while ensuring sufficient weld width during welding to ensure welding quality.

[0073] In one embodiment, Figures 1 to 8 As shown, the housing 1 includes two first side panels 14 and two second side panels 15 that are oppositely arranged. The first side panels 14 and the second side panels 15 are connected in sequence. The ends of the two first side panels 14 and the two second side panels 15 on the same side are surrounded to form an opening. The cover plate 2 includes a first side edge 21 and a second side edge 22. There is a first seam 6 between the first side panel 14 and the first side edge 21. There is a second seam 7 between the second side panel 15 and the second side edge 22. The width of the second seam 7 is g, which satisfies 0≤g≤0.5mm. When the cover plate 2 is welded to the housing 1, the second side edge 22 of the cover plate 2 and the second side panel 15 of the housing 1 can be clamped by a clamping tool to return the second seam 7 to zero, thereby preventing the laser from leaking into and burning the electrode group 5 during welding.

[0074] It is worth mentioning that please refer to Figures 3 to 5 The inner wall surface of the first side plate 14 includes the embedded section 11, the shielding section 12 and the pole group accommodating section 13 arranged in sequence, 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 should be noted that since the inner wall surface of the second side panel 15 is not provided with a shielding section 12, and the inner fillet serves as a transition surface between the first side panel 14 and the second side panel 15, the shielding section 12 is not obvious. If the width b of the first seam 6 is too large, the laser will leak in at the position of the inner fillet.

[0076] It is worth mentioning that please refer to Figure 1 The upper ends of the two first side plates 14 and the upper ends of the two second side plates 15 are enclosed to form the above-mentioned opening.

[0077] In one embodiment, Figure 5 and Figure 6 As shown, the cover plate 2 is provided with a boss 8 on the side facing the accommodation space, and a guide portion 81 is formed on the periphery of the boss 8. The thickness of the boss 8 is L3, and 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, resulting in 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, resulting in low structural strength, and the guiding effect of the boss 8 is guaranteed.

[0078] In one embodiment, Figure 5 and Figure 6As shown, the guide portion 81 is a chamfered surface that matches the step surface, and there is an angle x between the step surface and the extended surface of the embedded section 11. The cover plate 2 includes an outer end surface and a side surface, the side surface is located in the circumference of the outer end surface and connected to the outer end surface, the side surface matches the embedded section 11, and there is an angle z between the chamfered surface and the extended surface of the side surface, and the angle z is greater than or equal to the angle x, and satisfies x ≥ 30° and z ≤ 60°. When x ≥ 30°, it is helpful to shield the laser from entering, and the step surface of the shielding section 12 can fully abut against the boss 8, play a supporting role for the boss 8, and improve the overall stability of the cover plate 2 formed by the cover plate 2 and the boss 8; when z ≤ 60°, it avoids interference between the boss 8 and the shielding section 12 of the shell 1, and the chamfered surface can play a good guiding role when the cover plate 2 is assembled into the shell.

[0079] It is worth noting that the outer end surface of the cover plate 2 is the side of the cover plate 2 facing away from the accommodating space of the housing 1 .

[0080] In this embodiment, when the shell 1 and the cover plate 2 are assembled and welded, the cover plate 2 and the periphery of the shell 1 are pre-spot welded before the welding process, so that the cover plate 2 is pre-fixed on the shell 1. The pre-spot welding points will fix the height difference between the upper surface of the cover plate 2 and the upper end surface of the shell 1, that is, it is necessary to ensure that L2-0.5≤d≤L2+0.5, so as to prepare for the subsequent full-circle welding. It is necessary to ensure that the compressive strength of the battery after full-circle welding is greater than 1.2Mpa and there is no leakage at the weld. The helium leak detection rate of the battery after full-circle welding is less than 1×10 -7 pa·m³ / s.

[0081] In order to verify that the matching structure of the shell 1 and the cover plate 2 of this embodiment has better welding quality and air tightness, the shell 1 of the same size is assembled with the cover plates 2 and bosses 8 of different sizes, and the welding quality and air tightness of the battery are tested. The test results of the embodiment battery and the comparative battery are shown in Table 2. It should be noted that the embodiment battery refers to a battery that meets the size requirements of this embodiment, and correspondingly, the comparative battery refers to a battery that does not meet the size requirements of this embodiment.

[0082] Table 2 Welding quality and air tightness test results

[0083]

[0084] It can be seen from Table 2 that in Example 1, L2=0.6mm, and the value of L2 satisfies L2≥0.5mm; b=0.1mm, and the value of b satisfies 0≤b≤0.2mm; R1=2.5mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 0.1mm≤d≤1.1mm, and in Example 1, d=0.63mm satisfies the requirements; after calculation, the value range of c is 0.2mm≤c≤0.5mm, and in Example 1, c=0.2mm satisfies the requirements; after calculation, the value range of R2 is 2mm≤R2≤2.5mm, and in Example 1, R2=2.4mm satisfies the requirements. In the battery of Example 1, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 1 meets the requirements.

[0085] It can be seen from Table 2 that in Example 2, L2=1.2mm, and the value of L2 satisfies L2≥0.5mm; b=0.1mm, and the value of b satisfies 0≤b≤0.2mm; R1=2.5mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 0.7mm≤d≤1.7mm, and in Example 2, d=0.75mm satisfies the requirements; after calculation, the value range of c is 0.2mm≤c≤0.5mm, and in Example 2, c=0.25mm satisfies the requirements; after calculation, the value range of R2 is 2mm≤R2≤2.5mm, and in Example 2, R2=2.4mm satisfies the requirements. In the battery of Example 2, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 2 meets the requirements.

[0086] As can be seen from Table 2, in Example 3, L2=1.5mm, and the value of L2 satisfies L2≥0.5mm; b=0.1mm, and the value of b satisfies 0≤b≤0.2mm; R1=2.5mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 1mm≤d≤2mm, and in Example 3, d=1.6mm satisfies the requirements; after calculation, the value range of c is 0.2mm≤c≤0.5mm, and in Example 3, c=0.26mm satisfies the requirements; after calculation, the value range of R2 is 2mm≤R2≤2.5mm, and in Example 3, R2=2.4mm satisfies the requirements. In the battery of Example 3, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 3 meets the requirements.

[0087] As can be seen from Table 2, in Example 4, L2=0.5mm, and the value of L2 satisfies L2≥0.5mm; b=0.2mm, and the value of b satisfies 0≤b≤0.2mm; R1=1.65mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 0mm≤d≤1mm, and in Example 4, d=0.9mm satisfies the requirements; after calculation, the value range of c is 0.4mm≤c≤0.5mm, and in Example 4, c=0.43mm satisfies the requirements; after calculation, the value range of R2 is 1.15mm≤R2≤1.65mm, and in Example 4, R2=1.5mm satisfies the requirements. In the battery of Example 4, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 4 meets the requirements.

[0088] As can be seen from Table 2, in Example 5, L2=0.7mm, and the value of L2 satisfies L2≥0.5mm; b=0.15mm, and the value of b satisfies 0≤b≤0.2mm; R1=1.5mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 0.2mm≤d≤1.2mm, and in Example 5, d=1.2mm satisfies the requirements; after calculation, the value range of c is 0.3mm≤c≤0.5mm, and in Example 5, c=0.33mm satisfies the requirements; after calculation, the value range of R2 is 1mm≤R2≤1.5mm, and in Example 5, R2=1.3mm satisfies the requirements. In the battery of Example 5, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 5 meets the requirements.

[0089] As can be seen from Table 2, in Example 6, L2=0.6mm, and the value of L2 satisfies L2≥0.5mm; b=0.05mm, and the value of b satisfies 0≤b≤0.2mm; R1=5mm, and the value of R1 satisfies 1.5mm≤R1≤5mm; after calculation, the value range of d is 0.1mm≤d≤1.1mm, and in Example 6, d=0.1mm satisfies the requirements; after calculation, the value range of c is 0.1mm≤c≤0.5mm, and in Example 6, c=0.5mm satisfies the requirements; after calculation, the value range of R2 is 4.5mm≤R2≤5mm, and in Example 6, R2=4.5mm satisfies the requirements. In the battery of Example 6, after the cover plate 2 is welded to the shell 1, no laser leaks into the inside of the shell 1, the welding quality of the matching part between the shell 1 and the cover plate 2 is good, and the welding strength is high, and the battery of Example 6 meets the requirements.

[0090] As can be seen from Table 2, in Comparative Example 1, L2=0.4mm, and the value of L2 is not within the range of L2≥0.5mm, which does not meet the requirements. Since the value of L2 is too small, the battery in Comparative Example 1 forms a molten bead after the cover plate 2 and the shell 1 are laser welded, and the compressive strength of the battery after welding is lower than 1.2Mpa, or even lower than 1Mpa, which does not meet the requirements.

[0091] It can be seen from Table 2 that in Comparative Example 2, after calculation, the value range of c is 0.2mm≤c≤0.5mm, while in Comparative Example 2, c=0.1mm does not meet the requirement. In the battery of Comparative Example 2, when the cover plate 2 and the shell 1 are welded, the shielding section 12 cannot block the laser, and the laser leaks into the shell 1, causing the electrode group 5 to be burned, which does not meet the requirement.

[0092] As can be seen from Table 2, in Comparative Example 3, after calculation, the value range of d is 0.7mm≤d≤1.7mm, and in Comparative Example 3, d=0.6mm does not meet the requirement. Since the depth of the inlay section 11 is too small, the battery in Comparative Example 3 has problems of cold welding and hole explosion in the welding part after the cover plate 2 and the shell 1 are laser welded, and the side of the cover plate 2 away from the accommodation space protrudes from the end face of the shell 1 by more than 0.5mm, resulting in poor welding, and the helium leak detection rate does not meet the requirements.

[0093] As can be seen from Table 2, in Comparative Example 4, after calculation, the value range of d is 0.7mm≤d≤1.7mm, and in Comparative Example 4, d=1.8mm does not meet the requirement. Since the depth of the inlay section 11 is too large, the battery in Comparative Example 4 has problems of cold welding and hole explosion in the welding part after the cover plate 2 and the shell 1 are laser welded, and the side of the cover plate 2 away from the accommodation space sinks into the end face of the shell 1 by more than 0.5mm, resulting in poor welding, and the helium leak detection rate does not meet the requirements.

[0094] As can be seen from Table 2, in Comparative Example 5, b=0.3mm, and the value of b is not within the range of 0≤b≤0.2mm, which does not meet the requirements. In the battery of Comparative Example 5, when the cover plate 2 and the shell 1 are laser welded, the laser leaks into the position corresponding to the inner fillet of the shell 1, and the laser burns the four corners of the electrode group 5, which does not meet the requirements.

[0095] It can be seen from Table 2 that in Comparative Example 6, R1=1mm, and the value of R1 is not within the range of 1.5mm≤R1≤5mm, which does not meet the requirements. In the battery of Comparative Example 6, the trajectory is not continuous when the cover plate 2 and the shell 1 are welded, and there are cold welds and broken welds, and the helium leak detection rate does not meet the requirements.

[0096] According to another aspect of an embodiment of the present invention, a battery pack is provided, comprising the above-mentioned battery.

[0097] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: The shell has at least one end that is open; A cover plate is arranged corresponding to the opening to block the opening, the shell and the cover plate are enclosed to form a receiving space, the cover plate is welded to the shell to form a connecting section weld and a bursting section weld, the connecting section weld and the bursting section weld are connected end to end along the circumference of the cover plate; the penetration depth of the connecting section weld is greater than the penetration depth of the bursting section weld, and / or the fusion width of the connecting section weld is greater than the fusion width of the bursting section weld; A pole group is arranged in the accommodation space; The connecting section weld is arranged corresponding to one side of the cover plate, and the rest is the blasting section weld. The length of the connecting section weld is Y, and the length of the side of the cover plate where the connecting section weld is located is L, satisfying L / 2≤Y≤L-20, and the units of Y and L are both mm.

2. The battery according to claim 1, characterized in that The weld width of the connecting section weld is w1, and the weld width of the blasting section weld is w2, satisfying 1.2×w2≤w1≤1.5×w2; and / or, The penetration depth of the connecting section weld is h1, and the penetration depth of the blasting section weld is h2, satisfying 1.2×h2≤h1≤1.5×h2.

3. The battery according to claim 2, characterized in that The weld width w1 of the connecting section weld satisfies w1≥0.8mm; and / or, The penetration depth h1 of the welding seam of the connecting section satisfies 0.8 mm ≤ h1 ≤ 1 mm; and / or, The molten width w2 of the blasting section weld satisfies 0.5mm≤w2≤0.7mm; and / or, The penetration depth h2 of the blasting section weld satisfies 0.5mm≤h2≤0.7mm.

4. The battery according to claim 1, characterized in that The inner wall surface of the shell includes an embedding section, a shielding section and a pole group accommodating section. The four corners of the cover plate are interference fit with the embedding section, and the rest of the cover plate is clearance fit with the embedding section. The depth of the embedding section is d, and the thickness of the cover plate is L2, satisfying L2-0.5≤d≤L2+0.5, L2≥0.5mm, and the units of d and L2 are both mm.

5. The battery according to claim 4, characterized in that 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, and a first seam is provided between the embedded section and the cover plate, the width of the first seam is b, and 2b≤c≤0.5mm, 0≤b≤0.2mm is satisfied; and / or, Two adjacent side plates of the shell are connected by an inner fillet transition, the radius of the inner fillet is R1, and two adjacent side edges of the cover plate are connected by an outer fillet transition, the radius of the outer fillet is R2, and 1.5mm≤R1≤5mm, 0≤R1-R2≤0.5mm is satisfied; and / or, The wall thickness of the inlay section is a, which satisfies 0.3 mm ≤ a ≤ 1 mm.

6. The battery according to claim 5, characterized in that The shell includes two first side panels and two second side panels that are opposite to each other, the first side panels are connected to the second side panels in sequence, and the ends of the two first side panels and the two second side panels on the same side are arranged to form the opening, the cover panel includes a first side edge and a second side edge, the first seam is formed between the first side panel and the first side edge, the second seam is formed between the second side panel and the second side edge, and the width of the second seam is g, satisfying 0≤g≤0.5mm.

7. The battery according to claim 5, characterized in that The cover plate is provided with a boss on a 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, satisfying 0.7mm≤L1≤5mm, L3≥0.2mm.

8. The battery according to claim 7, characterized in that The guide portion is a chamfered surface that cooperates with the step surface, and an angle x is formed between the step surface and the extended surface of the embedding section. The cover plate includes an outer end surface and a side surface, and the side surface is located in the circumference of the outer end surface and connected to the outer end surface. The side surface cooperates with the embedding section, and an angle z is formed between the chamfered surface and the extended surface of the side surface, and the angle z is greater than or equal to the angle x, and satisfies x≥30° and z≤60°.

9. A battery pack, characterized in that: A battery comprising the battery according to any one of claims 1 to 8.

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