Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack. The pole group is positioned in the shell and is provided with a pole lug; the cover plate assembly is arranged at the opening end of the shell, the cover plate assembly comprises a cover plate body and a pole arranged on the cover plate body, and a welding hole penetrating through the pole in the vertical direction is formed in the pole; the connecting piece is arranged between the pole group and the cover plate assembly, the connecting piece comprises a first connecting area and a second connecting area, the first connecting area is welded with the pole lug, the second connecting area comprises an abutting part and a welding column, and the welding column is formed by extending a partial area of the upper surface of the abutting part towards the direction far away from the abutting part; the upper surface of the abutting part abuts against the lower surface of the pole, the welding column is arranged in the welding hole in a penetrating mode, and the peripheral surface of the welding column is welded to the inner wall of the welding hole. And the welding columns extend into the welding holes for matched welding, so that the influence of instantaneous impulsive force is avoided, and the qualification rate of the battery cell and the space utilization rate in the battery cell are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an electric core and a battery pack. Background Art

[0002] With the increasing development of battery technology, the industry has higher and higher requirements for the performance of electric cores. The electric core mainly includes a housing, a pole group, a cover plate and a connecting piece, etc. The connecting piece is connected between the pole column on the cover plate and the pole ear on the pole group to realize the electrical connection between the pole group and the pole column. During the assembly process of the electric core, usually, the pole column is first riveted to the cover plate body, and then the pole column is welded to the connecting piece. However, when the pole column is riveted to the cover plate body, the cover plate body is subjected to an instantaneous impact force, which will affect the stability of structures such as the explosion-proof valve provided on the cover plate body, thereby affecting the overall quality of the electric core. The qualified rate of the electric core is relatively low, and due to the existence of the riveting block, it seriously occupies the space along the axial direction of the pole column, resulting in a relatively low space utilization rate of the overall electric core. Summary of the Utility Model

[0003] In view of this, the utility model provides an electric core and a battery pack to solve the problems of relatively low qualified rate and relatively low space utilization rate of the electric core.

[0004] In a first aspect, the utility model provides an electric core, comprising: a housing having an open end; a pole group located inside the housing, the pole group having pole ears; a cover plate assembly provided at the open end of the housing, the cover plate assembly including a cover plate body and a pole column provided on the cover plate body, and a welding hole penetrating the pole column in the up and down direction is formed on the pole column; a connecting piece provided between the pole group and the cover plate assembly, the connecting piece including a first connection area and a second connection area, the first connection area is welded to the pole ear, the second connection area includes an abutting portion and a welding post, the welding post extends from a partial area on the upper surface of the abutting portion in a direction away from the abutting portion, the upper surface of the abutting portion abuts against the lower surface of the pole column, the welding post is inserted into the welding hole, and the outer peripheral surface of the welding post is welded to the inner wall of the welding hole.

[0005] Beneficial effects: A welding hole that penetrates up and down is constructed on the terminal post. The first connection area of the connecting piece includes an abutting portion and a welding post that protrudes from the upper surface of the abutting portion. The welding post extends into the welding hole to cooperate with it, and the upper surface of the abutting portion abuts against the lower surface of the terminal post, realizing the mutual positioning of the connecting piece and the terminal post. Further, the outer peripheral surface of the welding post is welded to the inner wall of the welding hole to realize the connection between the connecting piece and the terminal post. Compared with the traditional riveting method, the welding method is not affected by instantaneous impact force, which is beneficial to improving the qualification rate of the battery cell. And during the welding process, it can be operated from the side of the cover body far away from the electrode group. The welding track is along the gap between the welding post and the welding hole, with low operation difficulty, improving the assembly efficiency, and being convenient for observation, which is beneficial to ensuring the welding quality. Moreover, the structural form of inserting the welding post into the welding hole of the terminal post can also reduce the total size in the up and down direction after the assembly of the terminal post and the connecting piece, thereby improving the space utilization rate inside the battery cell, being beneficial to increasing the energy density of the battery cell. At the same time, the second connection area of the connecting piece is welded to the electrode tab of the electrode group, realizing the electrical connection between the connecting piece and the electrode group, and further realizing the connection between the electrode group and the terminal post through the connecting piece, leading the current inside the battery cell to the outside to complete the assembly of the battery cell.

[0006] In an optional embodiment, the circumferential area of contact between the welding post and the welding hole is greater than or equal to 3 mm 2 ; and / or, the cross-sectional area of the welding post in a cross-section perpendicular to its center line is greater than or equal to 1.5 mm 2 ; and / or, the height H0 of the welding post in the extending direction of its center line ranges from: 1.2 mm ≤ H0 ≤ 3.5 mm.

[0007] Beneficial effects: By setting the circumferential area of contact between the welding post and the welding hole to be greater than or equal to 3 mm 2 , the welding strength and current-carrying capacity can be guaranteed, thereby improving the performance of the battery cell. By setting the cross-sectional area of the welding post in a cross-section perpendicular to its center line to be greater than or equal to 1.5 mm 2 , the welding strength and current-carrying capacity can be guaranteed, thereby improving the performance of the battery cell. By setting the height H0 of the welding post in the range of 1.2 mm to 3.5 mm in the extending direction of its center line, both the welding strength and current-carrying capacity can be guaranteed, and the space utilization rate of the battery cell can be improved and the cost can be reduced.

[0008] In an optional embodiment, a groove is provided on the side of the terminal post away from the electrode group, and the welding hole penetrates the bottom wall of the groove.

[0009] Beneficial effects: By providing a groove on the upper side of the terminal post, the weight of the terminal post is reduced, which is beneficial to cost reduction. Moreover, the weld seam formed during the welding process between the welding post and the terminal post is located within the groove and does not protrude from the upper surface of the terminal post, avoiding affecting the connection between the upper surface of the terminal post and the bus bar, and further ensuring the connection performance between the battery cells or between the battery cells and the external circuit.

[0010] In an alternative embodiment, the upper surface of the welding post is flush with the bottom surface of the groove.

[0011] Beneficial effects: The plane where the bottom surface of the groove is located is relatively flat, avoiding interference with the welding equipment by the welding post or the bottom wall of the groove, facilitating the welding equipment to weld the welding post and the terminal post, and avoiding material waste, thereby saving costs.

[0012] In an alternative embodiment, the edge of the welding hole facing the abutting portion is configured as a chamfer to form a guiding surface.

[0013] Beneficial effects: By configuring the edge of the welding hole facing the abutting portion as a chamfer, the formed guiding surface provides guidance for the insertion of the welding post into the welding hole, facilitating the welding post to smoothly enter the welding hole, thereby improving the assembly efficiency.

[0014] In an alternative embodiment, a first through hole is provided in the cover plate body. The terminal post includes a first post segment and a second post segment. The outer contour of the second post segment is larger than that of the first post segment. The first post segment passes through the first through hole and abuts against the abutting portion, and the second post segment overlaps on the side of the cover plate body away from the electrode group.

[0015] Beneficial effects: By providing that the terminal post includes a first post segment and a second post segment and the outer contour of the second post segment is larger than that of the first post segment, the first post segment passes through the first through hole and the second post segment overlaps on the upper side of the cover plate body, facilitating the installation and positioning of the terminal post on the cover plate body. Further, through welding with the connecting piece and the cooperation of the sealing ring, the second plastic part, and the first plastic part, the terminal post can be fixed on the cover plate body without the traditional riveting process, with a simple structure, convenient operation, and high assembly efficiency.

[0016] In an alternative embodiment, the cover plate assembly further includes a first plastic part and a sealing ring. The first plastic part is provided on the lower side of the cover plate body. The sealing ring is sleeved on the outer peripheral surfaces of the first post segment and the abutting portion. The connecting piece further includes a transition zone that connects between the first connecting zone and the abutting portion. The abutting portion, the transition zone, and the first connecting zone are connected in a stepped manner. The upper surface of the transition zone abuts against a partial area on the lower surface of the first plastic part and the lower surface of the sealing ring.

[0017] Beneficial effects: The sealing ring is located between the outer peripheral surfaces of the first column section and the abutting part and the pole hole, achieving a sealing effect. The first plastic part is arranged to be combined with the lower surface of the cover plate body, ensuring the insulation between the connecting piece and the cover plate body, as well as the insulation between the electrode group and the cover plate body. And by setting the upper surface of the transition area of the connecting piece to abut against a partial area on the lower surface of the first plastic part and the lower surface of the sealing ring, the transition area presses the first plastic part and the sealing ring onto the cover plate body, thereby ensuring the relative stability between the components, ensuring insulation and sealing, and thus improving the safety and reliability of the battery cell.

[0018] In an optional embodiment, the distance between the upper surface and the lower surface of the abutting part is H1, the distance between the upper surface and the lower surface of the transition area is H2, and the distance between the upper surface and the lower surface of the first connection area is H3, where H3 ≤ H2 ≤ H1 ≤ H0.

[0019] Beneficial effects: 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 connection area is not greater than the thickness of the transition area and the thickness of the abutting part, ensuring that the thickness of the first connection area is within a reasonable range, so as to ensure the smooth realization of the welding between the first connection area and the tab.

[0020] In an optional embodiment, the value range of the distance H3 between the upper surface and the lower surface of the first connection area is: 0.2 mm ≤ H3 ≤ 2 mm.

[0021] Beneficial effects: It can not only ensure the structural strength of the first connection area, ensure the welding strength and welding quality, but also avoid the excessive weight of the connecting piece, thereby reducing costs.

[0022] In the second aspect, the present invention also provides a battery pack, including: the above-mentioned battery cell. Since the battery pack includes the battery cell, it has the same effects as the battery cell and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention 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 following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a schematic structural diagram of a battery cell according to an embodiment of the present invention;

[0025] Figure 2 is Figure 1 a top view of the battery cell shown;

[0026] Figure 3 is Figure 2 a sectional view taken along the A-A direction in

[0027] Figure 4 is Figure 3 a partially enlarged schematic view of B in

[0028] Figure 5 a schematic structural view of a connecting piece according to an embodiment of the present utility model;

[0029] Figure 6 is Figure 5 a top view of the connecting piece shown in

[0030] Figure 7 is Figure 6 a sectional view taken along the C-C direction in

[0031] Figure 8 a schematic structural view of a terminal according to an embodiment of the present utility model;

[0032] Figure 9 is Figure 8 a top view of the terminal shown in

[0033] Figure 10 is Figure 9 a sectional view taken along the D-D direction in

[0034] Figure 11 a schematic structural view of the welded structure of the terminal and the connecting piece according to an embodiment of the present utility model;

[0035] Figure 12 is Figure 11 a top view of the welded structure of the terminal and the connecting piece shown in

[0036] Figure 13 Figure 12 a sectional view taken along the E-E direction in

[0037] Explanation of reference numerals:

[0038] 1. housing; 2. electrode group; 201. tab; 202. electrode group body; 3. cover plate body; 4. terminal; 401. welding hole; 402. groove; 403. guiding surface; 410. first column section; 420. second column section; 5. connecting piece; 510. first connection area; 511. welding part; 512. avoidance hole; 520. second connection area; 521. abutting part; 522. welding post; 530. transition area; 6. first plastic part; 7. sealing ring; 8. second plastic part. Detailed implementation manners

[0039] 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 skilled 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.

[0040] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 13 , the embodiments of the present utility model will be described.

[0041] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, including: a housing 1, an electrode assembly 2, a cover plate assembly, and a connecting piece 5. The housing 1 has an open end; the electrode assembly 2 is located inside the housing 1, and the electrode assembly 2 has electrode tabs 201; the cover plate assembly is arranged at the open end of the housing 1, the cover plate assembly includes a cover plate body 3 and a pole column 4 arranged on the cover plate body 3, and a welding hole 401 penetrating the pole column 4 in the up and down direction is formed on the pole column 4; the connecting piece 5 is arranged between the electrode assembly 2 and the cover plate assembly, the connecting piece 5 includes a first connection area 510 and a second connection area 520, the first connection area 510 is welded to the electrode tab 201, the second connection area 520 includes an abutting portion 521 and a welding post 522, the welding post 522 extends from a partial area on the upper surface of the abutting portion 521 in a direction away from the abutting portion 521, the upper surface of the abutting portion 521 abuts against the lower surface of the pole column 4, the welding post 522 is inserted into the welding hole 401, and the outer peripheral surface of the welding post 522 is welded to the inner wall of the welding hole 401. Wherein, the up and down direction refers to the Figures 3 to 4 direction of "up and down" indicated by the arrow in Figures 3 to 4 ; the upper surface refers to the surface in the direction of "up" indicated by the arrow in Figures 3 to 4 ; the lower surface refers to the surface in the direction of "down" indicated by the arrow in

[0042] Applying the battery cell of this embodiment, a welding hole 401 that penetrates up and down is constructed on the terminal post 4. The first connection area 510 of the connecting piece 5 is provided to include an abutting portion 521 and a welding post 522 protruding from the upper surface of the abutting portion 521. The welding post 522 extends into the welding hole 401 to cooperate with it, and the upper surface of the abutting portion 521 abuts against the lower surface of the terminal post 4, so as to realize the mutual positioning of the connecting piece 5 and the terminal post 4. Further, the outer peripheral surface of the welding post 522 is welded to the inner wall of the welding hole 401 to realize the connection between the connecting piece 5 and the terminal post 4. Compared with the traditional riveting method, the welding method is not affected by instantaneous impact force, which is beneficial to improving the qualified rate of the battery cell. And during the welding process, it can be operated from the side of the cover body 3 far away from the electrode group 2. The welding track is along the gap between the welding post 522 and the welding hole 401, with low operation difficulty, improved assembly efficiency, and convenient observation, which is beneficial to ensuring the welding quality. Moreover, the structural form in which the welding post 522 is inserted into the welding hole 401 of the terminal post 4 can also reduce the total dimension in the up and down direction after the assembly of the terminal post 4 and the connecting piece 5, thereby improving the space utilization rate inside the battery cell, being beneficial to increasing the energy density of the battery cell. At the same time, the second connection area 520 of the connecting piece 5 is welded to the tab 201 of the electrode group 2, realizing the electrical connection between the connecting piece 5 and the electrode group 2. Furthermore, the electrode group 2 is connected to the terminal post 4 through the connecting piece 5, leading the current inside the battery cell to the outside, and completing the assembly of the battery cell.

[0043] In one embodiment, a first through hole is opened on the cover body 3. The terminal post 4 includes a first post section 410 and a second post section 420. The outer contour of the second post section 420 is larger than that of the first post section 410. The first post section 410 passes through the first through hole and abuts against the abutting portion 521, and the second post section 420 overlaps on the side of the cover body 3 far away from the electrode group 2. It should be noted that the outer contour of the second post section 420 is larger than the opening area of the first through hole on the cover body 3, and the outer contour of the first post section 410 is slightly smaller than the opening area of the first through hole on the cover body 3. The first through hole allows the first post section 410 to penetrate, and the second post section 420 cannot pass through the first through hole and is limited to the upper side of the cover body 3; the outer contour of the abutting portion 521 is equal in shape and size to that of the first post section 410, and the abutting portion 521 is arranged opposite to the first post section 410, so the abutting portion 521 can also penetrate into the first through hole, and the outer contour of the transition area 530 is larger than the opening area of the first through hole on the cover body 3 and is limited to the lower side of the cover body 3. Among them, the upper side refers to Figures 3 to 4 the side in the direction of the "up" indicated by the arrow.

[0044] By setting the terminal post 4 to include a first post segment 410 and a second post segment 420, and the outer contour of the second post segment 420 being larger than that of the first post segment 410, the first post segment 410 is passed through the first through hole and the second post segment 420 is lapped on the upper side of the cover body 3, which facilitates the installation and positioning of the terminal post 4 on the cover body 3. Further, through welding with the connecting piece 5 and the cooperation of the sealing ring 7, the second plastic part 8, and the first plastic part 6, the terminal post 4 can be fixed on the cover body 3 without the traditional riveting process, with a simple structure, convenient operation, and high assembly efficiency.

[0045] In one embodiment, the circumferential area of contact between the welding post 522 and the welding hole 401 is greater than or equal to 3 mm 2 . It should be noted that the welding of the outer peripheral surface of the welding post 522 and the inner wall of the welding hole 401 refers to the welding of the outer peripheral wall of the welding post 522 and the inner peripheral wall of the welding hole 401. The welding area after the two are welded serves as the current path. If the circumferential area of contact between the welding post 522 and the welding hole 401 is less than 3 mm 2 , it will result in insufficient welding area, thus too small an overcurrent area, affecting the overcurrent capacity, and the welding strength is weak, and the connection stability between the welding post 522 and the terminal post 4 is poor. Therefore, by setting the circumferential area of contact between the welding post 522 and the welding hole 401 to be greater than or equal to 3 mm 2 , the welding strength and overcurrent capacity can be ensured, thereby improving the performance of the battery cell. Preferably, the welding post 522 is a cylinder and the welding hole 401 is a round hole.

[0046] In one embodiment, the cross-sectional area of the welding post 522 in a cross-section perpendicular to its center line is greater than or equal to 1.5 mm 2 . Among them, the center line of the welding post 522 extends along the Figures 3 to 4 "up and down" direction indicated by the arrow in 2 . The cross-sectional area of the welding post 522 in a cross-section perpendicular to its center line is the cross-sectional area of the welding post 522. If the cross-sectional area of the welding post 522 is less than 1.5 mm 2 , the size of the welding post 522 is too small, resulting in too small a contact area between the welding post 522 and the welding hole 401, and thus insufficient welding area. Therefore, by setting the cross-sectional area of the welding post 522 in a cross-section perpendicular to its center line to be greater than or equal to 1.5 mm

[0047] In one embodiment, the height H0 of the welding post 522 along the extending direction of its center line ranges from 1.2 mm to 3.5 mm. If the height H0 of the welding post 522 is less than 1.2 mm, the height of the welding post 522 is too small, which will also result in too small a contact area between the welding post 522 and the welding hole 401, and thus insufficient welding area. If the height H0 of the welding post 522 is greater than 3.5 mm, the height of the welding post 522 is too large, occupying too much space in the up and down directions, which is not conducive to improving the space utilization rate of the battery cell, and will also make the connecting piece 5 too heavy, increasing the cost. Therefore, by setting the height H0 of the welding post 522 along the extending direction of its center line to be within the range of 1.2 mm to 3.5 mm, both the welding strength and the current-carrying capacity can be ensured, and the space utilization rate of the battery cell can be improved while reducing the cost.

[0048] In one embodiment, a groove 402 is provided on the side of the pole post 4 away from the pole group 2, and the welding hole 401 penetrates through the bottom wall of the groove 402. Among them, the side of the pole post 4 away from the pole group 2 is the upper side of the pole post 4. By providing the groove 402 on the upper side of the pole post 4, the weight of the pole post 4 is reduced, which is beneficial to cost reduction, and the weld formed during the welding process between the welding post 522 and the pole post 4 is located within the groove 402 and will not protrude from the upper surface of the pole post 4, avoiding affecting the connection between the upper surface of the pole post 4 and the bus bar, and further ensuring the connection performance between the battery cells or between the battery cell and the external circuit.

[0049] In one embodiment, the upper surface of the welding post 522 is flush with the bottom surface of the groove 402, so that the plane of the bottom surface of the groove 402 is relatively flat, avoiding interference of the welding post 522 or the bottom wall of the groove 402 with the welding equipment, facilitating the welding equipment to weld the welding post 522 and the pole post 4, and avoiding material waste, thus saving costs.

[0050] In one embodiment, further in combination with Figure 4 and Figure 10 as shown, the edge of the welding hole 401 facing the abutting portion 521 is configured as a chamfer to form a guiding surface 403. It should be noted that the side of the welding hole 401 facing the abutting portion 521 is the lower side of the welding hole 401. During the assembly process of the connecting piece 5 and the pole post 4, the welding post 522 is inserted into the welding hole 401 from the lower side of the welding hole 401. By configuring the edge of the welding hole 401 facing the abutting portion 521 as a chamfer, the formed guiding surface 403 provides guidance for the welding post 522 to be inserted into the welding hole 401, so as to facilitate the welding post 522 to smoothly enter the welding hole 401, thereby improving the assembly efficiency. Among them, the lower side refers to the side in the direction of "down" indicated by the arrow in Figure 10 .

[0051] In one embodiment, the cover plate assembly further includes a first plastic part 6 and a sealing ring 7. The first plastic part 6 is disposed on the lower side of the cover plate body 3, and the sealing ring 7 is sleeved on the outer circumferential surfaces of the first column section 410 and the abutting portion 521. The connecting piece 5 further includes a transition region 530, which is connected between the first connecting region 510 and the abutting portion 521. The abutting portion 521, the transition region 530, and the first connecting region 510 are connected in a stepped manner. The upper surface of the transition region 530 abuts against a partial region on the lower surface of the first plastic part 6 and the lower surface of the sealing ring 7. The sealing ring 7 is located between the outer circumferential surfaces of the first column section 410 and the abutting portion 521 and the pole post hole to achieve a sealing effect. The first plastic part 6 is disposed in combination with the lower surface of the cover plate body 3 to ensure the insulation between the connecting piece 5 and the cover plate body 3, as well as the insulation between the electrode group 2 and the cover plate body 3. And by setting the upper surface of the transition region 530 of the connecting piece 5 to abut against a partial region on the lower surface of the first plastic part 6 and the lower surface of the sealing ring 7, the transition region 530 presses the first plastic part 6 and the sealing ring 7 onto the cover plate body 3, thereby ensuring the relative stability between the components, ensuring insulation and sealing, and thus improving the safety and reliability of the battery cell.

[0052] It should be noted that the first connecting region of the connecting piece 5 is welded to the tab 201, and the second connecting region 520 is welded to the pole post 4. Along the Figure 3 "up and down" direction indicated by the arrow in the figure, there is a certain height difference between the pole post 4 and the tab 201. By setting the abutting portion 521, the transition region 530, and the first connecting region 510 to be connected in a stepped manner, while enabling the connecting piece 5 to adapt to the height difference between the pole post 4 and the tab 201, the material consumption is reduced, the cost is saved, the connecting piece 5 does not need to be bent, and the battery cell assembly efficiency is improved.

[0053] Specifically, 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 column section 410 and the abutting portion 521, and the second sealing section is located in the installation space formed among the lower surface of the cover plate body 3, the upper surface of the transition region 530, and the first plastic part 6.

[0054] In one embodiment, the cover plate assembly further includes a second plastic part 8, which is disposed between the upper surface of the cover plate body 3 and the second column section 420 to ensure the insulation between the second column section 420 and the cover plate body 3. Through the cooperation of the second plastic part 8, the sealing ring 7, and the first plastic part 6, the insulation and sealing between the pole post 4 and the connecting piece 5 and the cover plate body 3 are ensured respectively, thereby improving the safety and reliability of the battery cell. Among them, the sealing ring 7 has elasticity and is compressed during installation, with good sealing performance; the first plastic part 6 is a lower plastic, and the second plastic part 8 is an upper plastic.

[0055] In one embodiment, the distance between the upper surface and the lower surface of the abutting portion 521 is H1, the distance between the upper surface and the lower surface of the transition region 530 is H2, and the distance between the upper surface and the lower surface of the first connection region 510 is H3, where H3 ≤ H2 ≤ H1 ≤ H0. It should be noted that the distance between the upper surface and the lower surface of the abutting portion 521 is the thickness of the abutting portion 521, the distance between the upper surface and the lower surface of the transition region 530 is the thickness of the transition region 530, and the distance between the upper surface and the lower surface of the first connection region 510 is the thickness of the first connection region 510. Here, the upper surface refers to Figure 7 the surface in the direction of "up" indicated by the arrow in Figure 7 ; the lower surface refers to the surface in the direction of "down" indicated by the arrow in. The first connection region 510 is ultrasonically welded to the tab 201. If the thickness of the first connection region 510 is too large, it is difficult to achieve welding. By setting H3 ≤ H2 ≤ H1 ≤ H0, the connecting piece 5 is a product with variable wall thickness or equal wall thickness, which is easy to form, and the thickness of the first connection region 510 is not greater than the thickness of the transition region 530 and the abutting portion 521, ensuring that the thickness of the first connection region 510 is within a reasonable range, so as to ensure that the welding between the first connection region 510 and the tab 201 can be smoothly achieved.

[0056] Preferably, a groove is provided below the second connection region 520, which can further reduce the material used for the connecting piece 5, thereby reducing the weight of the connecting piece 5 and saving costs.

[0057] In one embodiment, the value range of the distance H3 between the upper surface and the lower surface of the first connection region 510 is: 0.2 mm ≤ H3 ≤ 2 mm. It should be noted that the electrode group 2 includes an electrode group body 202 and a tab 201. The first connection region 510 is welded to the tab 201 to lead the current inside the battery cell to the outside. If the thickness of the first connection region 510 is less than 0.2 mm, the first connection region 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, making it easy to break; if the thickness of the first connection region 510 is greater than 2 mm, the first connection region 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 connection region 510 within the range of 0.2 mm to 2 mm, the structural strength of the first connection region 510 can be ensured, the welding strength and welding quality can be guaranteed, and the excessive weight of the connecting piece 5 can be avoided, thereby reducing costs.

[0058] Preferably, the value range of the distance H3 between the upper surface and the lower surface of the first connection region 510 is: 0.4 mm - 0.8 mm, further improving the reliability of the first connection region 510.

[0059] In one embodiment, the number of the electrode groups 2 is four. Avoidance holes 512 are formed in the first connection area 510 of the connection piece 5 for the electrode tabs 201 to pass through. The avoidance holes 512 divide the first connection 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 lower part of the connection piece 5 upwards. Then, the electrode tabs 201 are bent by 90°, so that the part of the electrode tabs 201 above the first connection area 510 is attached to the upper surface of the welding part 511, and the electrode tabs 201 are welded to the upper surface of the welding part 511.

[0060] Specifically, the number of the connection pieces 5 is two. One connection piece 5 corresponds to the positive electrode tabs of the electrode groups 2, and the other connection 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 connection 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 connection 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 connection area 510 along its width direction. The same applies to the negative electrode tabs 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 connection piece 5, and the negative electrode post corresponds to the negative electrode tab and is connected through the other connection piece. Among them, the width direction refers to Figure 11 the "width direction" indicated by the arrow in the figure; the electrode posts 4 and the connection pieces 5 can be formed by stamping once without secondary processing, with simple structure and low cost.

[0061] It should be noted that during the cell assembly process, the connection piece 5 is first welded to the electrode tabs 201 of the electrode group 2. Specifically, as Figures 11 to 13 shown, the first connection area 510 of the connection piece 5 is welded to the electrode tabs 201. The second connection area 520 is located at a position corresponding to the electrode post 4 and the welding post 522 is placed upwards. After the electrode tabs 201 pass through the first connection area 510 from the lower part of the connection piece 5 upwards, they are bent by 90° towards the upper surface of the welding part 511, and then the electrode tabs 201 are welded to the welding part 511; then the connection piece 5 is welded to the electrode post 4. Specifically, the second plastic part 8 and the electrode post 4 are inserted from the upper side of the cover plate body 3, and the sealing ring 7, the first plastic part 6 and the connection piece 5 are assembled from the lower part of the cover plate body 3. The welding post 522 is inserted into the welding hole 401 and laser welded. The inner wall of the welding hole 401 and the outer wall of the welding post 522 are melted by laser, so as to realize the electrical connection between the electrode post 4 and the connection piece 5; finally, the cover plate body 3 is welded to the housing 1 to complete the assembly of the cell. The assembled cell is as Figures 1 to 3 shown. The assembly efficiency and performance are improved, the production yield is improved, and the space utilization rate inside the cell is improved.

[0062] According to an embodiment of the present utility model, on the other hand, a battery pack is further provided, including: the above-mentioned battery cells. Preferably, the number of battery cells is multiple.

[0063] Although the embodiments of the present utility model are 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 utility model, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing having an open end; A pole group located inside the housing, the pole group having pole tabs; A cover plate assembly provided at the open end of the housing, the cover plate assembly including a cover plate body and a pole post provided on the cover plate body, and a welding hole penetrating the pole post in the up-down direction is formed on the pole post; A connecting piece provided between the pole group and the cover plate assembly, the connecting piece including a first connecting area and a second connecting area, the first connecting area is welded to the pole tab, the second connecting area includes an abutting portion and a welding post, the welding post extends from a partial area of the upper surface of the abutting portion in a direction away from the abutting portion, the upper surface of the abutting portion abuts against the lower surface of the pole post, the welding post is inserted into the welding hole, and the outer peripheral surface of the welding post is welded to the inner wall of the welding hole.

2. The battery cell according to claim 1, wherein, The circumferential area of contact between the welding post and the welding hole is greater than or equal to 3 mm 2 ; And / or, the cross-sectional area of the welding post in a cross-section perpendicular to its center line is greater than or equal to 1.5 mm 2 ; And / or, the value range of the height H0 of the welding post along the extending direction of its center line is: 1.2mm ≤ H0 ≤ 3.5mm.

3. The battery cell according to claim 1, wherein, A groove is formed on one side of the pole post away from the pole group, and the welding hole penetrates the bottom wall of the groove.

4. The battery cell according to claim 3, wherein, The upper surface of the welding post is flush with the bottom surface of the groove.

5. The battery cell according to claim 1, characterized in that, The edge of the welding hole on the side facing the abutting portion is configured as a chamfer to form a guiding surface.

6. The battery cell according to any one of claims 1 to 5, characterized in that, A first through hole is formed on the cover plate body, the pole post includes a first post section and a second post section, the outer contour of the second post section is larger than that of the first post section, the first post section is inserted into the first through hole and abuts against the abutting portion, and the second post section overlaps on the side of the cover plate body away from the pole group.

7. The battery cell according to claim 6, characterized in that, The cover plate assembly further includes a first plastic part and a sealing ring, the first plastic part is provided on the lower side of the cover plate body, and the sealing ring is sleeved on the outer peripheral surfaces of the first post section and the abutting portion; The connecting piece further includes a transition area, the transition area is connected between the first connecting area and the abutting portion, the abutting portion, the transition area and the first connecting area are connected in a stepped manner, and the upper surface of the transition area abuts against a partial area of the lower surface of the first plastic part and the lower surface of the sealing ring.

8. The cell according to claim 7, characterized in that, The distance between the upper surface and the lower surface of the abutting portion is H1, the distance between the upper surface and the lower surface of the transition area is H2, and the distance between the upper surface and the lower surface of the first connecting area is H3, wherein, H3 ≤ H2 ≤ H1 ≤ H0.

9. The battery cell according to claim 8, wherein, The value range of the distance H3 between the upper surface and the lower surface of the first connecting area is: 0.2mm ≤ H3 ≤ 2mm.

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

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