Battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery and a battery pack, and the battery comprises a shell, a pole group and a cover plate assembly, the lower surface of the first boss on the pole abuts against and is welded to the upper surface of the second boss on the connecting piece, connection of the pole and the connecting piece is achieved, the plate body part and the area, except the second boss, of the connecting piece are located on the upper side and the lower side of the cover plate body respectively, installation of the pole on the cover plate body is achieved, the structure is simple, efficiency is high, and cost is low. The welding groove is formed in the side, away from the pole, of the second welding area, the welding device extends into the welding groove to weld the second boss and the first boss from bottom to top, it is avoided that a weld joint is formed on the upper surface of the pole to affect connection of the pole and the busbar, the weld joint is located in the welding groove and cannot make contact with the pole set, and safety is high; the weight of the connecting piece is reduced, the penetrating distance needed by welding laser is reduced, welding of the second boss and the first boss is conveniently achieved, needed laser energy is reduced, and cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a battery and a battery pack. Background Art

[0002] A battery mainly consists of a housing, an electrode assembly and a cover plate assembly. The electrode assembly is located inside the housing, and the cover plate assembly is arranged at the open end of the housing to seal the housing. A connecting piece is arranged between the electrode assembly and the cover plate assembly. The connecting piece is respectively welded to the pole column on the cover plate assembly and the pole ear on the electrode assembly to realize the electrical connection between the electrode assembly and the pole column. The side of the pole column far from the electrode assembly is used for subsequent connection with a bus bar, so as to realize the electrical connection between this battery and other batteries or with an external circuit. During the battery assembly process, usually after the connecting piece is welded to the pole ear on the electrode assembly, the pole column on the cover plate assembly is then welded to the connecting piece.

[0003] However, in the above assembly process, the welding operation is usually carried out from the side of the cover plate assembly far from the electrode assembly, that is, from the side of the pole column far from the electrode assembly. When welding, it is necessary to penetrate the pole column to realize the welding between the pole column and the connecting piece. However, the thickness dimension of the pole column is usually large and it is difficult to be penetrated by a laser. The distance that the laser needs to penetrate is long. Therefore, the required laser energy is large, and the weld seam is easy to protrude from the surface of the pole column, affecting the connection between the pole column and the bus bar, thereby affecting the current-carrying area of the battery. Summary of the Utility Model

[0004] In view of this, the utility model provides a battery and a battery pack to solve the problems that the distance that the welding laser needs to penetrate is long and the weld seam affects the connection between the pole column and the bus bar.

[0005] In a first aspect, the utility model provides a battery, comprising: a housing having an open end; an electrode assembly arranged inside the housing, the electrode assembly having a pole ear; a cover plate assembly arranged at the open end of the housing, the cover plate assembly including a cover plate body, a pole column and a connecting piece. The cover plate body is provided with a pole column hole. The pole column includes a plate body part and a first boss protruding from the lower surface of the plate body part. The first boss is inserted into the pole column hole, and the plate body part is lapped on the upper side of the cover plate body. The connecting piece is arranged on the lower side of the cover plate body. The connecting piece includes a first welding area and a second welding area. The first welding area is welded to the pole ear. The second welding area includes a connecting part and a second boss. The connecting part is connected to one side edge of the first welding area. The second boss protrudes from the upper surface of the connecting part. The upper surface of the second boss abuts against the lower surface of the first boss. A welding groove corresponding to the second boss is arranged on the lower side of the second welding area. The welding groove is adapted to allow a welding device to weld the second boss and the first boss.

[0006] Beneficial effects: By setting the lower surface of the first boss on the terminal post to abut against the upper surface of the second boss on the connecting piece, and welding the second boss and the first boss, the connection between the terminal post and the connecting piece is realized. At the same time, the first boss is inserted into the terminal post hole, and the plate body part and the area of the connecting piece other than the second boss are respectively located on the upper and lower sides of the cover plate body. Then, the installation of the terminal post on the cover plate body can be realized by welding the first boss and the second boss, reducing the traditional riveting process or the welding ring assembly process. The structure is simple and the assembly efficiency is high. Moreover, by providing a welding groove on the side of the second welding area away from the terminal post, the welding device extends into the welding groove and welds the second boss and the first boss from bottom to top, that is, the welding position is located on the lower side of the cover plate body, which can avoid forming a weld on the upper surface of the terminal post and affecting the connection between the terminal post and the bus bar. And the weld formed by welding is located in the welding groove and will not contact the electrode group below the connecting piece, with high safety. In addition, by providing the welding groove, the thickness of the solid part of the second welding area corresponding to the welding groove in the up and down direction is reduced, reducing the distance that the welding laser needs to penetrate, facilitating the welding of the second boss and the first boss, reducing the required laser energy, and reducing the weight of the connecting piece, which is beneficial to cost reduction.

[0007] In an optional embodiment, the thickness of the first boss is T1, and the thickness of the solid part of the second welding area corresponding to the welding groove in the up and down direction is H1, where T1≥H1.

[0008] Beneficial effects: By setting the thickness T1 of the first boss to be greater than or equal to the thickness H1 of the solid part of the second welding area corresponding to the welding groove in the up and down direction, the structural strength of the first boss is enhanced. While ensuring that the laser welding can penetrate the bottom wall of the welding groove to realize the welding of the second boss and the first boss, it avoids laser penetration of the first boss, thus ensuring the stability of the welding mating surface and the welding quality.

[0009] In an optional embodiment, the value range of the thickness H1 of the solid part of the second welding area corresponding to the welding groove in the up and down direction is: 1mm - 2mm.

[0010] Beneficial effects: It can not only ensure the structural strength of the second welding area and the welding strength of the second boss, but also avoid welding defects caused by excessive welding power, thereby improving the welding quality.

[0011] In an alternative embodiment, the upper surface of the second boss has the same shape and size as the lower surface of the first boss. The cover plate assembly further includes: a first plastic part disposed between the upper surface of the cover plate body and the plate body part; a second plastic part disposed on the lower side of the cover plate body, with a partial area of the second plastic part located between a partial area of the upper surface of the connecting part and the lower surface of the cover plate body; a sealing ring including a first sealing section and a second sealing section, the first sealing section being sleeved on the outer peripheral surfaces of the first boss and the second boss, and the second sealing section being located in the installation space formed between the lower surface of the cover plate body, the upper surface of the connecting part, and the second plastic part.

[0012] Beneficial effects: Protected by the first plastic part, the sealing ring, and the second plastic part, the insulation and sealing between the pole post and the connecting piece and the cover plate body are ensured, thereby improving the safety and reliability of the battery. Among them, the sealing ring has elasticity and is compressed during installation, with good sealing performance.

[0013] In an alternative embodiment, the center line of the second boss coincides with the center line of the connecting part. The upper surface of the connecting part forms an abutting surface, and the abutting surface abuts against a partial area of the lower surface of the second plastic part and the lower surface of the sealing ring. The abutting surface is annular, and the value range of the annular width L of the ring is: L≥0.8mm.

[0014] Beneficial effects: By setting the center line of the second boss to coincide with the center line of the connecting part, the second boss is located at the center position of the connecting part, which is convenient for processing and has good structural stability. The connecting part is connected to the lower side of the second boss, and the upper surface of the connecting part surrounds the circumference of the second boss. The upper surface of the connecting part abuts against a partial area of the lower surface of the second plastic part and the lower surface of the sealing ring to press the second plastic part and the sealing ring against the lower surface of the cover plate body to ensure the compression amount of the sealing ring and ensure the sealing effect. The annular abutting surface can improve the assembly stability. At the same time, setting the annular width L of the ring to be greater than or equal to 0.8mm ensures that the connecting part and the second plastic part have sufficient contact area, thereby ensuring that the second plastic part is closely attached to the cover plate body.

[0015] In an alternative embodiment, the lower surface of the pole post is above the lower surface of the cover plate body or flush with the lower surface of the cover plate body. The thickness of the cover plate body is T0, and the distance between the lower surface of the pole post and the lower surface of the cover plate body is H0, where 0≤H0 / T0≤0.56.

[0016] Beneficial effects: By setting the lower surface of the terminal post above the lower surface of the cover plate body or flush with the lower surface of the cover plate body, it is ensured that the first boss does not protrude from the terminal post hole. Then, the second boss extends into the terminal post hole to cooperate with the first boss or the upper surface of the second boss is flush with the lower surface of the cover plate body, which can achieve the purpose of reducing the total dimension of the terminal post in the up-and-down direction after welding with the connecting piece. At the same time, by setting H0 / T0 ≤ 0.56, the thickness of the first boss is prevented from being too small, thus ensuring that the terminal post has sufficient strength. Therefore, by setting H0 / T0 to take values within the range of 0 to 0.56, the total dimension of the terminal post in the up-and-down direction after welding with the connecting piece can be reduced, thereby improving the utilization rate of the internal space of the battery, and the terminal post can have sufficient strength to ensure the reliability of the battery.

[0017] In an optional embodiment, the value range of the thickness T0 of the cover plate body is: 1.2 mm ≤ T0 ≤ 2.5 mm; and / or, the value range of the distance H0 between the lower surface of the terminal post and the lower surface of the cover plate body is: 0 ≤ H0 ≤ 1.4 mm.

[0018] Beneficial effects: By setting the thickness T0 of the cover plate body to take values within the range of 1.2 mm to 2.5 mm, it can not only ensure that the cover plate body has sufficient strength, but also avoid the cover plate body being too heavy, thus ensuring the safety of the battery and controlling the cost. By setting the distance H0 between the lower surface of the terminal post and the lower surface of the cover plate body to take values within the range of 0 to 1.4 mm, it can not only ensure the improvement of the utilization rate of the internal space of the battery, but also ensure that the terminal post has sufficient strength and ensure the welding strength.

[0019] In an optional embodiment, the upper surface of the connecting portion is above the upper surface of the first welding area, and the thickness H2 of the connecting portion, the thickness H3 of the first welding area, and the thickness H1 of the solid portion of the second welding area corresponding to the welding groove in the up-and-down direction satisfy the relational expression: H1 ≥ H2 ≥ H3.

[0020] Beneficial effects: By setting the upper surface of the connecting portion above the upper surface of the first welding area, and since the upper surface of the second boss is above the upper surface of the connecting portion, the connecting piece is in a stepped shape as a whole. While ensuring the welding of the second welding area with the terminal post and the abutment with the second plastic part, the upper surface of the first welding area is spaced from the second plastic part, thereby providing space for the welding of the tab with the first welding area and avoiding crushing the tab. At the same time, by setting H1 ≥ H2 ≥ H3, the connecting piece is a product with variable wall thickness or equal wall thickness, which is easy to mold, and the thickness of the first welding area is not greater than the thickness of the connecting portion and the thickness of the solid portion of the second welding area corresponding to the welding groove in the up-and-down direction, ensuring the smooth realization of the welding between the first welding area and the tab.

[0021] In an alternative embodiment, the thickness H3 of the first welding area ranges from 0.2 mm to 1.5 mm.

[0022] Beneficial effects: It can not only ensure the structural strength of the first welding area, guarantee the welding strength and welding quality, but also avoid the excessive weight of the connecting piece, thereby reducing costs.

[0023] Second, the present utility model also provides a battery pack, including: the above-mentioned battery. Since the battery pack includes the battery and has the same effects as the battery, they will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 Structural schematic diagram of a battery according to an embodiment of the present utility model;

[0026] Figure 2 For Figure 1 Top view of the battery shown;

[0027] Figure 3 For Figure 2 Cross-sectional view in the A-A direction in;

[0028] Figure 4 For Figure 3 Partial enlarged schematic diagram of B in;

[0029] Figure 5 Structural schematic diagram of a connecting piece according to an embodiment of the present utility model;

[0030] Figure 6 For Figure 5 Top view of the connecting piece shown;

[0031] Figure 7 For Figure 6 Cross-sectional view in the C-C direction in;

[0032] Figure 8 Structural schematic diagram of a pole according to an embodiment of the present utility model;

[0033] Figure 9 For Figure 8 Top view of the pole shown;

[0034] Figure 10 For the positive pole of the embodiment of the present utility model alongFigure 9 Cross-sectional view in the D-D direction;

[0035] Figure 11 This is a cross-sectional view of the negative electrode post of the embodiment of the present utility model along Figure 9 the D-D direction;

[0036] Figure 12 This is a schematic structural diagram of the welding structure of the electrode post and the connecting piece of the embodiment of the present utility model;

[0037] Figure 13 It is Figure 12 the top view of the welding structure of the electrode post and the connecting piece shown;

[0038] Figure 14 This is a cross-sectional view of the welding structure of the positive electrode post and the connecting piece of the embodiment of the present utility model along Figure 13 the E-E direction;

[0039] Figure 15 This is a cross-sectional view of the welding structure of the negative electrode post and the connecting piece of the embodiment of the present utility model along Figure 13 the E-E direction;

[0040] Figure 16 This is a schematic structural diagram of the welding structure of the electrode group and the connecting piece of the embodiment of the present utility model;

[0041] Figure 17 It is Figure 16 the top view of the welding structure of the electrode group and the connecting piece shown;

[0042] Figure 18 It is Figure 17 a cross-sectional view in the F-F direction.

[0043] Explanation of reference numerals:

[0044] 1. Housing; 2. Electrode group; 201. Tab; 202. Electrode group body; 3. Cover body; 4. Electrode post; 410. First boss; 420. Plate part; 5. Connecting piece; 510. First welding area; 511. Welding part; 512. Avoidance hole; 520. Second welding area; 521. Second boss; 522. Connecting part; 523. Welding groove; 6. Second plastic part; 7. Sealing ring; 8. First plastic part. Detailed implementation manners

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0046] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 18 , the embodiments of the present utility model will be described.

[0047] According to an embodiment of the present utility model, on the one hand, a battery is provided, including: a housing 1, an electrode assembly 2, and a cover plate assembly. The housing 1 has an open end; the electrode assembly 2 is disposed inside the housing 1, and the electrode assembly 2 has an electrode tab 201; the cover plate assembly is disposed at the open end of the housing 1, and the cover plate assembly includes a cover plate body 3, a terminal post 4, and a connecting piece 5. The cover plate body 3 is provided with a terminal post hole. The terminal post 4 includes a plate body portion 420 and a first boss 410 protruding from the lower surface of the plate body portion 420. The first boss 410 is inserted into the terminal post hole, and the plate body portion 420 is lapped on the upper side of the cover plate body 3. The connecting piece 5 is disposed on the lower side of the cover plate body 3; the connecting piece 5 includes a first welding area 510 and a second welding area 520. The first welding area 510 is welded to the electrode tab 201. The second welding area 520 includes a connecting portion 522 and a second boss 521. The connecting portion 522 is connected to one side edge of the first welding area 510. The second boss 521 protrudes from the upper surface of the connecting portion 522. The upper surface of the second boss 521 abuts against the lower surface of the first boss 410. A welding groove 523 corresponding to the second boss 521 is disposed on the lower side of the second welding area 520. The welding groove 523 is adapted to allow a welding device to weld the second boss 521 and the first boss 410.

[0048] Among them, the upper side refers to Figures 3 to 4 the side in the direction of "up" indicated by the arrow in Figures 3 to 4 ; the lower side refers to Figures 3 to 4 the side in the direction of "down" indicated by the arrow in Figures 3 to 4 ; the lower surface refers to Figures 3 to 4 the surface in the direction of "down" indicated by the arrow in

[0049] When applying the battery of this embodiment, by setting the lower surface of the first boss 410 on the pole post 4 to abut against the upper surface of the second boss 521 on the connecting piece 5, and welding the second boss 521 and the first boss 410, the connection between the pole post 4 and the connecting piece 5 is realized. At the same time, the first boss 410 is inserted into the pole post hole, and the plate body part 420 and the area of the connecting piece 5 other than the second boss 521 are respectively located on the upper and lower sides of the cover plate body 3. Then, the installation of the pole post 4 on the cover plate body 3 can be realized by welding the first boss 410 and the second boss 521, reducing the traditional riveting process or the welding ring assembly process, and without the influence of the instantaneous impact force during riveting. The structure is simple and the assembly efficiency is high. Moreover, by setting the welding groove 523 on the side of the second welding area 520 far from the pole post 4, the welding device extends into the welding groove 523 and welds the second boss 521 and the first boss 410 from bottom to top, that is, the welding position is located on the lower side of the cover plate body 3, which can avoid forming a weld on the upper surface of the pole post 4 and affecting the connection between the pole post 4 and the bus bar. And the weld formed by welding is located in the welding groove 523 and will not contact the electrode group 2 below the connecting piece 5, so the safety is relatively high. In addition, by setting the welding groove 523, the thickness of the solid part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction is reduced, reducing the distance that the welding laser needs to penetrate, facilitating the welding of the second boss 521 and the first boss 410, reducing the required laser energy, and reducing the weight of the connecting piece 5, which is beneficial to reducing costs.

[0050] It should be noted that during the battery assembly process, first weld the first welding area 510 of the connecting piece 5 with the pole ear 201 to realize the connection between the connecting piece 5 and the electrode group 2, and then weld the second boss 521 of the connecting piece 5 with the pole post 4 in the cover plate assembly to realize the connection between the connecting piece 5 and the cover plate assembly. Finally, install the electrode group 2, the connecting piece 5 and the cover plate assembly as a whole into the housing 1, and weld the cover plate body 3 and the housing 1 to realize sealing. Among them, the welding method between the second boss 521 and the first boss 410 is laser penetration welding. The welding groove 523 is recessed upward from the lower surface of the second welding area 520. During welding, the welding head of the welding device is inserted into the welding groove 523, and the second boss 521 and the first boss 410 are welded from bottom to top; the electrode group 2 includes an electrode group body 202 and a pole ear 201, and the number of electrode groups 2 is multiple. Before being installed into the housing 1, there is a gap between the electrode group bodies 202 of different electrode groups 2. Therefore, when the welding device performs welding operations from below the connecting piece 5, the electrode group body 202 will not interfere with the welding head.

[0051] It should be noted that the orthographic projection area of the first boss 410 on the upper surface of the cover plate body 3 is slightly smaller than the opening area of the pole hole on the cover plate body 3, and the pole hole allows the first boss 410 to penetrate; the orthographic projection area of the plate body part 420 on the upper surface of the cover plate body 3 is larger than the opening area of the pole hole on the cover plate body 3, and the plate body part 420 cannot pass through the pole hole, so it is limited to the upper side of the cover plate body 3; the orthographic projection area of the connecting part 522 on the upper surface of the cover plate body 3 is larger than the opening area of the pole hole on the cover plate body 3, so it is limited to the lower side of the cover plate body 3. The dividing line between the plate body part 420 and the first boss 410 is as Figures 10 to 11 shown by the dotted line in

[0052] In one embodiment, further in combination with Figure 3 and Figure 14 as shown, the thickness of the first boss 410 is T1, and the thickness of the entity part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction is H1, where T1≥H1. It should be noted that the thickness of the first boss 410 refers to the dimension of the first boss 410 in the up and down direction; the thickness of the entity part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction is the thickness of the bottom wall of the welding groove 523, that is, the dimension of the bottom wall of the welding groove 523 in the up and down direction, where the up and down direction refers to Figure 3 and Figure 14 the direction of "up and down" indicated by the arrow in

[0053] During the welding process of the pole 4 and the connecting piece 5, the welding device welds from below the welding groove 523, and the welding laser penetrates the bottom wall of the welding groove 523 from bottom to top and then reaches the first boss 410, so as to realize the welding of the second boss 521 and the first boss 410. A welding mating surface is formed between the second boss 521 and the first boss 410 after welding. By setting the thickness T1 of the first boss 410 to be greater than or equal to the thickness H1 of the entity part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction, the structural strength of the first boss 410 is enhanced, ensuring that the laser welding can penetrate the bottom wall of the welding groove 523 to realize the welding of the second boss 521 and the first boss 410, while avoiding laser penetration of the first boss 410, thus ensuring the stability of the welding mating surface and the welding quality.

[0054] In one embodiment, the thickness H1 of the solid part of the second welding area 520 corresponding to the welding groove 523 in the up-down direction ranges from 1 mm to 2 mm, that is, the wall thickness of the bottom wall of the welding groove 523 ranges from 1 mm to 2 mm. If the thickness H1 of the solid part of the second welding area 520 corresponding to the welding groove 523 in the up-down direction is less than 1 mm, the bottom wall of the welding groove 523 is too thin, the structural stability is poor and it is easily welded through, affecting the welding strength. If the thickness H1 of the solid part of the second welding area 520 corresponding to the welding groove 523 in the up-down direction is greater than 2 mm, the bottom wall of the welding groove 523 is too thick, the required welding power is too large, and defects such as welding pores are likely to occur. Therefore, by setting the thickness H1 of the solid part of the second welding area 520 corresponding to the welding groove 523 in the up-down direction to be within the range of 1 mm to 2 mm, both the structural strength of the second welding area 520 and the welding strength of the second boss 521 can be ensured, and welding defects caused by excessive welding power can be avoided, thereby improving the welding quality.

[0055] In one embodiment, the projected area of the welding groove 523 on the upper surface of the second boss 521 is smaller than the area of the upper surface of the second boss 521, that is, the circumferential profile of the welding groove 523 is smaller than the circumferential profile of the second boss 521. Then the welding groove 523 can extend into the second boss 521. While ensuring that the second boss 521 has sufficient structural strength, the wall thickness of the bottom wall of the welding groove 523 can be further reduced according to requirements, which is beneficial to further reducing the welding power and the weight of the connecting piece 5, thereby reducing the cost.

[0056] In one embodiment, the upper surface of the second boss 521 has the same shape and size as the lower surface of the first boss 410, and the second boss 521 faces the first boss 410. The cover assembly further includes: a first plastic part 8, a second plastic part 6 and a sealing ring 7. The first plastic part 8 is arranged between the upper surface of the cover body 3 and the plate body part 420; the second plastic part 6 is arranged on the lower side of the cover body 3, and a partial area of the second plastic part 6 is located between a partial area of the upper surface of the connecting part 522 and the lower surface of the cover body 3; the sealing ring 7 includes a first sealing section and a second sealing section. The first sealing section is sleeved on the outer circumferential surfaces of the first boss 410 and the second boss 521, and the second sealing section is located in the installation space formed among the lower surface of the cover body 3, the upper surface of the connecting part 522 and the second plastic part 6. At positions where the pole 4 and the connecting piece 5 may contact the cover body 3 respectively, protection is carried out through the first plastic part 8, the sealing ring 7 and the second plastic part 6 to ensure insulation and sealing between the pole 4 and the connecting piece 5 and the cover body 3 respectively, thereby improving the safety and reliability of the battery. Among them, the sealing ring 7 has elasticity and is compressed during installation, with good sealing performance; the second plastic part 6 is a lower plastic, and the first plastic part 8 is an upper plastic.

[0057] In one embodiment, the center line of the second boss 521 coincides with the center line of the connecting portion 522. The upper surface of the connecting portion 522 forms an abutting surface which abuts against a partial area of the lower surface of the second plastic part 6 and the lower surface of the sealing ring 7. The abutting surface is annular, and the value range of the annular width L of the ring is: L≥0.8 mm. By setting the center line of the second boss 521 to coincide with the center line of the connecting portion 522, the second boss 521 is located at the central position of the connecting portion 522, which is convenient for processing and has good structural stability. The connecting portion 522 is connected to the lower side of the second boss 521. The upper surface of the connecting portion 522 surrounds the circumference of the second boss 521. The upper surface of the connecting portion 522 abuts against a partial area of the lower surface of the second plastic part 6 and the lower surface of the sealing ring 7 to press the second plastic part 6 and the sealing ring 7 against the lower surface of the cover body 3 to ensure the compression amount of the sealing ring 7 and ensure the sealing effect. The annular abutting surface can improve the assembly stability. At the same time, by setting the annular width L to be greater than or equal to 0.8 mm, it is ensured that the connecting portion 522 and the second plastic part 6 have sufficient contact area, so as to ensure that the second plastic part 6 is closely attached to the cover body 3.

[0058] In one embodiment, further in combination with Figure 4 as shown, the lower surface of the pole column 4 is located above the lower surface of the cover body 3 or flush with the lower surface of the cover body 3, that is, the lower surface of the pole column 4 is not lower than the lower surface of the cover body 3. The thickness of the cover body 3 is T0, and the distance between the lower surface of the pole column 4 and the lower surface of the cover body 3 is H0. Among them, 0≤H0 / T0≤0.56. Among them, the thickness of the cover body 3 refers to the dimension of the cover body 3 along the Figure 4 "up and down" direction indicated by the arrow in. By setting the lower surface of the pole column 4 to be located above the lower surface of the cover body 3 or flush with the lower surface of the cover body 3, it is ensured that the first boss 410 will not protrude from the pole column hole, then the second boss 521 extends into the pole column hole to cooperate with the first boss 410 or the upper surface of the second boss 521 is flush with the lower surface of the cover body 3, that is, H0 / T0≥0, so as to achieve the purpose of reducing the total dimension of the pole column 4 and the connecting piece 5 in the up and down direction after welding. At the same time, by setting H0 / T0 to be less than or equal to 0.56, it is avoided that the thickness of the first boss 410 is too small, so as to ensure that the pole column 4 has sufficient strength. Therefore, by setting the value of H0 / T0 in the range of 0 to 0.56, it is possible to reduce the total dimension of the pole column 4 and the connecting piece 5 in the up and down direction after welding, thereby improving the utilization rate of the internal space of the battery, and at the same time ensuring that the pole column 4 has sufficient strength and ensuring the reliability of the battery.

[0059] In one embodiment, the value range of the thickness T0 of the cover plate body 3 is: 1.2 mm ≤ T0 ≤ 2.5 mm. The cover plate body 3 is a light aluminum plate. If the thickness of the cover plate body 3 is less than 1.2 mm, the thickness of the cover plate body 3 is too small, the strength of the cover plate body 3 is insufficient, and the battery safety is poor; if the thickness of the cover plate body 3 is greater than 2.5 mm, the thickness of the cover plate body 3 is too large, the weight is too large, and the cost increases. Therefore, by setting the thickness T0 of the cover plate body 3 to be within the range of 1.2 mm to 2.5 mm, it is possible to ensure that the cover plate body 3 has sufficient strength and avoid excessive weight of the cover plate body 3, thereby ensuring the battery safety and controlling the cost.

[0060] In one embodiment, the value range of the distance H0 between the lower surface of the pole column 4 and the lower surface of the cover plate body 3 is: 0 ≤ H0 ≤ 1.4 mm. If the distance between the lower surface of the pole column 4 and the lower surface of the cover plate body 3 is less than 0, that is, the lower surface of the pole column 4 is located below the lower surface of the cover plate body 3, the size in the up and down direction is increased, which is not conducive to improving the space utilization rate inside the battery and the energy density of the battery; if the distance between the lower surface of the pole column 4 and the lower surface of the cover plate body 3 is greater than 1.4 mm, the thickness of the first boss 410 is too small, the structural strength is insufficient, and the reliability after welding is poor. Therefore, by setting the distance H0 between the lower surface of the pole column 4 and the lower surface of the cover plate body 3 to be within the range of 0 to 1.4 mm, it is possible to ensure the improvement of the space utilization rate inside the battery and ensure that the pole column 4 has sufficient strength and ensure the welding strength.

[0061] Preferably, the value range of the distance H0 between the lower surface of the pole column 4 and the lower surface of the cover plate body 3 is 0 < H0 ≤ 1.4 mm, that is, the lower surface of the pole column 4 is located above the lower surface of the cover plate body 3, and the welding mating surface formed by welding the first boss 410 and the second boss 521 is located within the pole column hole, which has a better protection effect on the welding mating surface.

[0062] In one embodiment, further combined with Figure 7 As shown, the upper surface of the connecting portion 522 is located above the upper surface of the first welding area 510, and the thickness H2 of the connecting portion 522, the thickness H3 of the first welding area 510, and the thickness H1 of the entity portion of the second welding area 520 corresponding to the welding groove 523 in the up and down direction satisfy the relational expression: H1 ≥ H2 ≥ H3. Among them, the thickness refers to along Figure 7The dimension in the "up and down" direction indicated by the arrow. By setting the upper surface of the connecting portion 522 above the upper surface of the first welding area 510, and since the upper surface of the second boss 521 is above the upper surface of the connecting portion 522, the connecting piece 5 as a whole is in a stepped shape. While ensuring the welding of the second welding area 520 to the pole column 4 and abutting against the second plastic part 6, it makes a space between the upper surface of the first welding area 510 and the second plastic part 6, thus providing space for the welding of the tab 201 to the first welding area 510, avoiding damaging the tab. At the same time, by setting H1≥H2≥H3, the connecting piece 5 is a product with variable wall thickness or equal wall thickness, which is easy to mold, and the thickness of the first welding area 510 is not greater than the thickness of the connecting portion 522 and the thickness of the entity part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction, ensuring the smooth realization of the welding between the first welding area 510 and the tab 201.

[0063] It should be noted that for the ultrasonic welding between the first welding area 510 and the tab 201, if the thickness of the first welding area 510 is too large, it is difficult to achieve welding. Therefore, by setting the thickness of the first welding area 510 to be less than or equal to the thickness of the connecting portion 522 and the thickness of the entity part of the second welding area 520 corresponding to the welding groove 523 in the up and down direction, the thickness of the first welding area 510 is ensured to be within a reasonable range, thus realizing the welding between the first welding area 510 and the tab 201.

[0064] In one embodiment, the value range of the thickness H3 of the first welding area 510 is: 0.2mm ≤ H3 ≤ 1.5mm. The first welding area 510 is welded to the tab 201 to lead the current inside the battery to the outside. The thickness of the first welding area 510 is the dimension of the first welding area 510 in the up and down direction. If the thickness of the first welding area 510 is less than 0.2mm, the first welding area 510 is too thin and lacks strength, and it is easy to be welded through during the welding process with the tab 201, and the welding strength is insufficient after welding, being prone to breakage; if the thickness of the first welding area 510 is greater than 1.5mm, the first welding area 510 is too thick, with too much weight and high cost, and it is difficult to ensure the welding quality with the tab 201. Therefore, by setting the thickness H3 of the first welding area 510 to be within the range of 0.2mm to 1.5mm, it can not only ensure the structural strength of the first welding area 510, ensure the welding strength and welding quality, but also avoid the excessive weight of the connecting piece 5, thus reducing the cost.

[0065] In one embodiment, the number of the electrode groups 2 is four. Avoidance holes 512 are formed in the first welding area 510 of the connecting piece 5 for the electrode tabs 201 to pass through. The avoidance holes 512 divide the first welding area 510 into two welding parts 511. Each welding part 511 corresponds to two electrode groups 2. The electrode tabs 201 pass through the avoidance holes 512 from the bottom to the top below the connecting piece 5, and then the electrode tabs 201 are bent by 90°. The part of the electrode tab 201 above the first welding area 510 is attached to the upper surface of the welding part 511, and the electrode tab 201 is welded to the upper surface of the welding part 511.

[0066] Specifically, the number of the connecting pieces 5 is two. One connecting piece 5 corresponds to the positive electrode tabs of the electrode groups 2, and the other connecting piece 5 corresponds to the negative electrode tabs of the electrode groups 2. The four electrode groups 2 are arranged in sequence. In the arrangement direction, the positive electrode tabs of the first electrode group 2 and the second electrode group 2 are connected to one welding part 511 of the connecting piece 5, and the positive electrode tabs of the third electrode group 2 and the fourth electrode group 2 are connected to the other welding part 511 of the same connecting piece 5. The positive electrode tabs of the second electrode group 2 and the third electrode group 2 in the middle pass through the avoidance holes 512, and the electrode tabs 201 of the first electrode group 2 and the fourth electrode group 2 on both sides pass through both sides of the first welding area 510 in its width direction. The situation of the negative electrode tabs is the same and will not be elaborated here. The number of the electrode posts 4 is two, one is a positive electrode post and the other is a negative electrode post. The positive electrode post corresponds to the positive electrode tab and is connected through one connecting piece 5, and the negative electrode post corresponds to the negative electrode tab and is connected through the other connecting piece. Wherein, the width direction refers to Figure 16 the "width direction" indicated by the arrow in the figure.

[0067] Among them, the positive electrode post is an aluminum electrode post (as Figure 10 shown), the negative electrode post is a copper-aluminum composite electrode post (as Figure 11 shown). The material of the connecting piece 5 connecting the positive electrode post and the positive electrode tab is aluminum, and the material of the connecting piece 5 connecting the negative electrode post and the negative electrode tab is copper. The aluminum electrode post, the copper-aluminum composite electrode post and the connecting piece 5 can all be formed by stamping at one time without secondary processing, with simple structure and low cost.

[0068] It should be noted that during the battery assembly process, the connecting piece 5 is first welded to the electrode tab 201 of the electrode group 2. Specifically, as Figures 16 to 18As shown, align the first welding area 510 of the connecting piece 5 with the position of the tab 201. The second welding area 520 is located at a position corresponding to the terminal post, and the second boss 521 faces upward. After passing through the first welding area 510 from below to above under the tab 201, the tab 201 is bent 90° to the upper surface of the welding part 511, and then the welding part 511 is welded to the tab 201. Then assemble the cover plate assembly and weld the terminal post 4 on the cover plate assembly to the connecting piece 5. Specifically, the first plastic part 8 and the terminal post 4 are inserted from the upper side of the cover plate body 3, and the sealing ring 7, the second plastic part 6 and the connecting piece 5 are assembled from the lower side of the cover plate body 3. Then, the welding device laser-welds the terminal post 4 and the connecting piece 5 from the welding groove 523 below the second welding area 520. Finally, the electrode group 2, the connecting piece 5 and the cover plate assembly are integrally installed in the housing 1, and the cover plate body 3 is welded to the housing 1 to complete the assembly of the battery. The assembled battery is as shown in Figures 1 to 3 shown. The assembly efficiency and performance are improved, the production yield is increased, and the space utilization rate inside the battery is improved.

[0069] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery. Preferably, the number of batteries is multiple, and the multiple batteries are connected in series or in parallel.

[0070] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, Comprising: A housing having an open end; A pole group disposed inside the housing, the pole group having pole tabs; A cover plate assembly disposed at the open end of the housing, the cover plate assembly including a cover plate body, a pole post and a connecting piece. The cover plate body is provided with a pole post hole. The pole post includes a plate body portion and a first boss protruding from the lower surface of the plate body portion. The first boss is inserted through the pole post hole, the plate body portion is lapped on the upper side of the cover plate body, and the connecting piece is disposed on the lower side of the cover plate body; The connecting piece includes a first welding area and a second welding area. The first welding area is welded to the pole tab. The second welding area includes a connecting portion and a second boss. The connecting portion is connected to one side edge of the first welding area. The second boss protrudes from the upper surface of the connecting portion. The upper surface of the second boss abuts against the lower surface of the first boss. A welding groove corresponding to the second boss is provided on the lower side of the second welding area. The welding groove is adapted to allow a welding device to weld the second boss and the first boss.

2. The battery according to claim 1, wherein The thickness of the first boss is T1, and the thickness of the solid portion of the second welding area corresponding to the welding groove in the up and down direction is H1, where T1≥H1.

3. The battery according to claim 2, characterized in that, The value range of the thickness H1 of the solid portion of the second welding area corresponding to the welding groove in the up and down direction is: 1 mm - 2 mm.

4. The battery according to claim 1, characterized in that, The upper surface of the second boss and the lower surface of the first boss are equal in shape and size. The cover plate assembly further includes: A first plastic part disposed between the upper surface of the cover plate body and the plate body portion; A second plastic part disposed on the lower side of the cover plate body, and a partial area of the second plastic part is located between a partial area of the upper surface of the connecting portion and the lower surface of the cover plate body; A sealing ring, the sealing ring including a first sealing section and a second sealing section. The first sealing section is sleeved on the outer peripheral surfaces of the first boss and the second boss. The second sealing section is located in the installation space formed between the lower surface of the cover plate body, the upper surface of the connecting portion and the second plastic part.

5. The battery according to claim 4, characterized in that, The center line of the second boss coincides with the center line of the connecting portion. The upper surface of the connecting portion forms an abutting surface. The abutting surface abuts against a partial area of the lower surface of the second plastic part and the lower surface of the sealing ring. The abutting surface is annular, and the value range of the ring width L of the annulus is: L≥0.8 mm.

6. The battery according to claim 1, characterized in that, The lower surface of the pole post is above the lower surface of the cover plate body or flush with the lower surface of the cover plate body. The thickness of the cover plate body is T0, and the distance between the lower surface of the pole post and the lower surface of the cover plate body is H0, where 0≤H0 / T0≤0.

56.

7. The battery according to claim 6, characterized in that, The value range of the thickness T0 of the cover plate body is: 1.2 mm≤T0≤2.5 mm; And / or, the value range of the distance H0 between the lower surface of the pole post and the lower surface of the cover plate body is: 0≤H0≤1.4 mm.

8. The battery according to any one of claims 1 to 7, characterized in that The upper surface of the connecting portion is located above the upper surface of the first welding zone. A relational expression is satisfied among the thickness H2 of the connecting portion, the thickness H3 of the first welding zone, and the thickness H1 of the solid portion corresponding to the welding groove in the up-and-down direction of the second welding zone: H1≥H2≥H3.

9. The battery according to claim 8, characterized in that, The value range of the thickness H3 of the first welding zone is: 0.2 mm ≤ H3 ≤ 1.5 mm.

10. A battery pack, characterized in that, Comprising: The battery according to any one of claims 1 to 9.

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