Battery cell and battery pack

Abstract

The utility model relates to the technical field of power batteries, and discloses a battery cell and a battery pack, the battery cell comprises a shell, and the upper side of the shell is provided with an opening; the peripheral contour of the cover plate is matched with the contour of the opening, and a pair of through grooves is formed in the cover plate; the connecting pieces are arranged on the lower side of the cover plate, and one ends of the connecting pieces extend to the lower side of the through groove and are opposite to the through groove; the pole group is arranged in the shell, one end of the pole group is provided with pole lugs, and the pole lugs are arranged in one-to-one correspondence with the pair of through grooves; the peripheral contours of the sealing plates are matched with the corresponding through grooves respectively, the sealing plates are welded to the groove walls of the through grooves, at least one connecting groove is formed in the lower side plate face of each sealing plate, and the groove opening size of each connecting groove is larger than the groove bottom size; the pair of insulation pads are arranged on the lower sides of the corresponding sealing plates, the insulation pads and the sealing plates are connected in a hot melting mode and form welding parts with the same number as the connecting grooves, and the welding parts are matched with the connecting grooves.

Description

Technical Field

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

[0002] The power battery is the main power source of new energy vehicles, responsible for providing continuous and stable electrical energy for the vehicle. The power battery is composed of multiple battery cell units connected in series. Each battery cell structure includes an internal electrode group and a housing. The electrode group is provided with positive and negative electrode tabs for leading out the current of the electrode group, and the housing is provided with electrode posts. The electrode posts are connected to the corresponding electrode tabs through connecting pieces, thereby connecting the battery cell to the circuit.

[0003] In the related art, a channel for welding the electrode tabs is usually provided on the housing of the battery cell. After the staff completes the welding operation of the electrode tabs and related components through this channel, a sealing plate is required to seal the housing to keep the inside of the battery cell in a closed state and protect the electrode tabs and related structures. At the same time, in order to prevent the sealing plate from being short-circuited with structures such as the electrode tabs, an insulating pad is usually provided on the lower side of the sealing plate to separate the sealing plate from the lower-side structure.

[0004] However, in the above-mentioned related art, during the assembly process of the battery cell and in the process steps of evacuating and injecting electrolyte of the battery cell, the insulating pad is disturbed by air, electrolyte or other components, which may cause the insulating pad to deviate from its original position, and then it is easy for the sealing plate to be short-circuited with charged components such as the electrode tabs, resulting in a potential safety hazard of shell leakage. Summary of the Utility Model

[0005] In view of this, the utility model provides a battery cell and a battery pack to solve the problem that the insulating pad is prone to shift during the processing of the battery cell, resulting in a potential safety hazard of shell leakage.

[0006] In a first aspect, the utility model provides a battery cell, including: a housing with an opening on the upper side; a cover plate, the circumferential contour of which is adapted to the contour of the opening, and a pair of through grooves are opened on the cover plate; a pair of connecting pieces, arranged on the lower side of the cover plate, one end of the connecting piece extends to the lower side of the through groove and is arranged opposite to the through groove; an electrode group, arranged in the housing, and two groups of electrode tabs are arranged at one end of the electrode group, and the two groups of electrode tabs are respectively arranged corresponding to a pair of through grooves; a pair of sealing plates, the circumferential contours of which are respectively adapted to the corresponding through grooves and are welded to the groove walls of the through grooves, at least one connecting groove is arranged on the lower side plate surface of the sealing plate, and the size of the groove opening of the connecting groove is larger than the size of the groove bottom; a pair of insulating pads, arranged on the lower side of the corresponding sealing plate, and the insulating pads are heat-melted and connected to the sealing plates to form welding parts with the same number as the connecting grooves, and the welding parts are adapted to the connecting grooves.

[0007] Beneficial effects: The split assembly design of the housing and the cover plate facilitates the insertion of the electrode group into the housing. The cover plate is provided to close the top opening of the housing, realizing the limitation and protection of the electrode group. A through groove is opened on the cover plate, and the tab of the electrode group is led out from the position of the through groove, which is convenient for the staff to operate on the tab after the battery is assembled. By providing a sealing plate to close the through groove, the cover plate is closed after the staff completes the operation on the tab, protecting structures such as the tab. An insulating pad is provided on the lower side of the sealing plate to isolate the sealing plate from structures such as the tab on the lower side of the sealing plate. The staff sets at least one connecting groove on the lower side of the sealing plate, and the insulating pad is fixed to the sealing plate in a form of heat fusion connection, so that the insulating pad and the sealing plate as a whole have good bonding strength. At the same time, during the heat fusion connection process, a plurality of welding parts are formed on the insulating pad and filled in the connecting groove. Since the notch size of the connecting groove is smaller than the bottom size of the groove, it is difficult for the welding part to withdraw from the connecting groove, thereby forming a more stable and firm connection, avoiding the situation that the insulating pad detaches from the sealing plate during subsequent assembly, vacuum pumping, liquid injection and other processes, resulting in potential safety hazards of housing leakage.

[0008] In an optional embodiment, the connecting groove is a frustum-shaped groove, the notch diameter of the connecting groove is d, the bottom diameter of the connecting groove is D, and D - d ≥ 0.3 mm is satisfied.

[0009] Beneficial effects: Since the notch diameter of the connecting groove is smaller than the bottom diameter, and the bottom diameter is at least 0.3 mm larger than the notch diameter, after the insulating pad and the sealing plate are heat fusion connected, it is prevented that the difference between the notch size and the bottom size is too small, resulting in the welding part being easily detached from the connecting groove and the insulating pad being easily detached from the sealing plate. At the same time, it is also prevented that the difference between the notch size and the bottom size is too large, resulting in the molten material forming the welding part during the heat fusion process being difficult to fill the connecting groove, thereby reducing the bonding area between the welding part and the groove wall of the connecting groove, weakening the bonding strength, and making the insulating pad easily detach from the sealing plate.

[0010] In an optional embodiment, the distance between the upper side surface of the sealing plate and the bottom of the connecting groove is t, and 1.5 mm ≥ t ≥ 0.2 mm.

[0011] Beneficial effects: The staff controls the distance between the bottom of the connecting groove and the upper side surface of the sealing plate, thereby reserving enough depth for the connecting groove, and further enabling the sealing plate and the insulating pad to have sufficient bonding strength. At the same time, it also avoids the situation that the thickness of the sealing plate at the position of the connecting groove is too small, resulting in weak structural strength, easy breakage, electrolyte leakage of the battery cell, etc., affecting the battery quality, and improving the reliability of the battery cell.

[0012] In an optional embodiment, the depth of the connecting groove is H, and 1.2 mm ≥ H ≥ 0.3 mm.

[0013] Beneficial effects: By controlling the depth of the connection groove, the staff can avoid the situation where the connection strength between the sealing plate and the insulating pad is weak due to the too small depth of the connection groove, and also avoid the situation where when the sealing plate and the insulating pad are heat-melt connected, the molten material cannot fully fill the connection groove, affecting the connection strength due to the too large depth of the connection groove. In addition, it can also avoid the situation where the depth of the connection groove is set too large, resulting in the too thin thickness of the sealing plate at the connection groove, affecting the structural strength of the sealing plate.

[0014] In an optional embodiment, a plurality of connection grooves are provided, and the connection grooves are arranged in a matrix or linearly on the sealing plate.

[0015] Beneficial effects: By arranging the connection grooves in a matrix or linearly on the sealing plate, when the sealing plate and the insulating pad are heat-melt connected, while the molten material combines with the sealing plate to form a fixing method similar to integral bonding, stronger bonding points are formed at the positions of the connection grooves and the welding parts between the sealing plate and the insulating pad. The multiple bonding points are distributed on the surface of the sealing plate and act on the insulating pad together, which can effectively avoid the situation where the insulating pad is partially separated from the sealing plate, and further improve the bonding stability between the sealing plate and the insulating pad.

[0016] In an optional embodiment, a pair of pole columns are provided on the cover plate, the pole columns penetrate through the cover plate, one end of the connecting piece abuts against the bottom end of the pole column, the pole ear extends towards the cover plate and bends towards the connecting piece, and the bent part of the pole ear abuts against the upper surface of the connecting piece.

[0017] Beneficial effects: Since one end of the connecting piece under the cover plate is located at the lower end of the corresponding pole column and is connected to the pole column, and the other end extends laterally to a position opposite to the through groove, it is convenient to connect with the pole ear, enabling the staff to conveniently perform welding operations on the pole ear and the connecting piece through the through groove position. Because the pole ear led out from the pole group is arranged opposite to the corresponding through groove and is located laterally of the corresponding pole column, when electrically connecting the pole ear and the pole column, the connecting piece can be set into an approximately flat plate-like structure, thus saving the longitudinal space inside the housing. In addition, since the connecting piece is set into an approximately flat plate-like structure, when the pole ear is connected to the connecting piece, the pole ear has more sufficient bending space, which is convenient for controlling the bending angle of the pole ear to improve the connection stability between the pole ear and the connecting piece, and can also further reduce the occupation of the longitudinal space inside the housing.

[0018] In an alternative embodiment, a connection hole is provided at a position on the cover plate corresponding to the pole column. The pole column passes through the connection hole and is connected to the cover plate. A sealing ring and a first insulating member are provided inside the connection hole. The sealing ring surrounds the circumference of the pole column and separates the pole column from the cover plate. The first insulating member extends in the direction of the through groove parallel to the plate surface of the cover plate and separates the connection piece from the cover plate.

[0019] Advantageous effects: By providing the sealing ring and the first insulating member, with the sealing ring arranged around the pole column, the sealing performance at the connection hole is improved, avoiding the leakage of the battery core liquid and the entry of external liquid into the battery core. At the same time, the pole column is also separated from the cover plate to avoid short circuit. The first insulating member is arranged on the upper side of the connection piece to separate the connection piece from the cover plate and the sealing plate, avoiding the short circuit between the connection piece and the cover plate and the sealing plate, preventing the leakage of electricity from the housing, and improving the reliability of the battery core.

[0020] In an alternative embodiment, a second insulating member is provided on the side of the cover plate facing the inside of the housing. The second insulating member is located between a pair of the through grooves and extends in the direction of the two through grooves and separates the connection piece from the cover plate.

[0021] Advantageous effects: By providing the second insulating member at the position between the two through grooves on the cover plate, the part of the cover plate between the two through grooves is separated from the end of the connection piece extending towards the middle of the cover plate, enabling the connection piece to extend to the side of the through groove close to the middle of the cover plate. Thus, it has sufficient length and will not be short-circuited with the cover plate, effectively avoiding the leakage of electricity from the housing. In addition, since the connection piece has sufficient length, it also provides sufficient space for the connection between the connection piece and the tab, reducing the situation that the poor contact between the tab and the connection piece affects the performance of the battery core.

[0022] In an alternative embodiment, a liquid injection hole penetrating the cover plate in the thickness direction is provided on the cover plate, and the liquid injection hole is arranged between a pair of the through grooves.

[0023] Advantageous effects: By arranging the liquid injection hole on the cover plate, the liquid injection hole is located on the upper side of the battery core. Thus, during the processing of the battery core, processing operations such as the assembly of the electrode group, the welding of the cover plate, the bending of the tab, the welding of the tab and the connection piece, the welding of the sealing plate and the connection piece, and the liquid injection of the battery core can all be carried out from the same side of the housing, simplifying the assembly steps and facilitating the reduction of the difficulty of the automated design of the battery core assembly line.

[0024] In a second aspect, the present invention further provides a battery pack, including: a plurality of the above-mentioned battery cores.

[0025] Beneficial effects: The battery cell group in the battery pack is composed of the above-mentioned battery cells, thereby improving the reliability of the battery pack. At the same time, the sealing plate and the insulating pad have reliable connection strength, greatly reducing the occurrence of electric leakage after the battery cells are assembled, improving the product reliability, and enhancing the production efficiency of the battery pack. Brief Description of the Drawings

[0026] 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 use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a schematic diagram of the overall structure of a battery cell according to an embodiment of the present invention;

[0028] Figure 2 It is a schematic cross-sectional view of a battery cell according to an embodiment of the present invention for the combined structure of a sealing plate and an insulating pad;

[0029] Figure 3 For Figure 2 a partial enlarged view of A in

[0030] Figure 4 It is a schematic diagram of a battery cell according to an embodiment of the present invention for showing the structure of a sealing pad and a welding part;

[0031] Figure 5 It is a schematic cross-sectional view of the internal structure of a battery cell according to an embodiment of the present invention;

[0032] Figure 6 For Figure 5 a partial enlarged view of B in

[0033] Figure 7 It is a schematic diagram of a battery cell according to an embodiment of the present invention for showing the structure of the electrode group before the ear is bent;

[0034] Figure 8 It is a schematic diagram of a battery cell according to an embodiment of the present invention for showing the structure of the electrode group after the ear is bent.

[0035] Explanation of the reference numerals:

[0036] 100, housing; 200, cover plate; 201, through groove; 202, connection hole; 203, terminal post; 204, liquid injection hole; 300, connection piece; 400, electrode group; 401, tab; 500, sealing plate; 501, connection groove; 600, insulating pad; 601, welding part; 701, first insulating part; 702, second insulating part; 703, sealing ring. Detailed implementation manners

[0037] 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. Obviously, the described embodiments are some but not all of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0038] The following combines Figures 1 to 8 , to describe the embodiments of the present utility model.

[0039] According to an embodiment of the present utility model, on the one hand, a battery cell is provided. Please refer to Figure 1 and Figure 2 , including: a housing 100, a cover plate 200, an electrode group 400, a pair of sealing plates 500 and a pair of insulating pads 600. There is an opening on the upper side of the housing 100; the peripheral contour of the cover plate 200 is adapted to the contour of the opening, and a pair of through grooves 201 are formed on the cover plate 200; a pair of connection pieces 300 are arranged on the lower side of the cover plate 200, and one end of the connection piece 300 extends to the lower side of the through groove 201 and is arranged opposite to the through groove 201; the electrode group 400 is arranged in the housing 100, and two sets of tabs 401 are arranged at one end of the electrode group 400, and the two sets of tabs 401 are respectively arranged in one-to-one correspondence with the pair of through grooves 201; a pair of sealing plates 500, the peripheral contours of which are respectively adapted to the corresponding through grooves 201 and are welded to the groove walls of the through grooves 201. At least one connection groove 501 is arranged on the lower side plate surface of the sealing plate 500, and the size of the groove opening of the connection groove 501 is larger than the size of the groove bottom; the insulating pad 600 is arranged on the lower side of the sealing plate 500, and the insulating pad 600 is heat-melted and connected to the sealing plate 500 to form welding parts 601 with the same number as the connection grooves 501, and the welding parts 601 are adapted to the connection grooves 501.

[0040] In this embodiment, the housing 100 and the cover plate 200 are designed for split assembly, which facilitates the installation of the electrode assembly 400 into the housing 100. The cover plate 200 is provided to close the top opening of the housing 100, so as to limit and protect the electrode assembly 400. A through groove 201 is formed in the cover plate 200, and the tab 401 of the electrode assembly 400 is led out from the position of the through groove 201, which is convenient for the staff to operate on the tab 401 after the battery is assembled. By providing a sealing plate 500 to close the through groove 201, the cover plate 200 is closed after the staff completes the operation on the tab 401, so as to protect structures such as the tab 401. An insulating pad 600 is arranged on the lower side of the sealing plate 500 to isolate the sealing plate 500 from structures such as the tab 401 on the lower side of the sealing plate 500. The staff sets at least one connecting groove 501 on the lower side of the sealing plate 500, and the insulating pad 600 is fixed to the sealing plate 500 in a form of hot melt connection, so that the insulating pad 600 and the sealing plate 500 have good bonding strength. At the same time, during the hot melt connection process, a plurality of welding parts 601 are formed on the insulating pad 600 and filled in the connecting groove 501. Since the notch size of the connecting groove 501 is smaller than the bottom size, the welding parts 601 are difficult to withdraw from the connecting groove 501, thereby forming a more stable and firm connection, and avoiding the situation that the insulating pad 600 is separated from the sealing plate 500 during subsequent processes such as assembly, vacuum pumping and liquid injection, resulting in potential safety hazards of electric leakage in the housing 100.

[0041] Specifically, the above embodiment does not limit the specific forms of the housing 100, the cover plate 200 and the through groove 201. The shapes and sizes of the housing 100 and the scraper are set according to the specific requirements of the battery cell product. The shape of the through groove 201 is determined according to the number, position of the tab 401 and the setting position of the connecting piece 300. Exemplarily, the housing 100 is set in a cuboid shape, the opening is arranged at the upper end of the housing 100, and the opening has the same cross-sectional shape as the housing 100. The cover plate 200 is adapted to the cross-sectional shape of the housing 100, and after the electrode assembly 400 is installed in the housing 100, at least part of the cover plate 200 is pressed into the opening, and finally the housing 100 and the cover plate 200 are connected by laser welding. The through groove 201 on the cover plate 200 is set in a rectangular shape, and the two through grooves 201 are symmetrically distributed on the cover plate 200 with respect to the central axis of the housing 100.

[0042] In addition, it should be noted that the shape of the welding part 601 formed on the insulating pad 600 depends on the specific shape of the connecting groove 501 on the sealing plate 500. The connecting groove 501 can be frustum-shaped. In some embodiments not shown, the connecting groove 501 can also be a T-shaped groove, a trapezoidal groove or other shapes, as long as the welded welding part 601 can form a structure with a top size larger than the bottom size. The specific forms of the above connecting grooves 501 are all within the protection scope of this embodiment.

[0043] In one embodiment, refer to Figure 3 , the connecting groove 501 is a frustum-shaped groove. The diameter of the notch of the connecting groove 501 is d, and the diameter of the bottom of the connecting groove 501 is D, and D - d ≥ 0.3 mm is satisfied.

[0044] Specifically, the notch of the connecting groove 501 refers to the opening of the connecting groove 501 facing the lower side. When the connecting groove 501 is arranged in a frustum shape, both the notch and the bottom of the connecting groove 501 are circular.

[0045] In this embodiment, since the diameter of the notch of the connecting groove 501 is smaller than the diameter of the bottom, and the diameter of the bottom is at least 0.3 mm larger than the diameter of the notch. After the insulating pad 600 is thermally fused to the sealing plate 500, it is prevented that the difference in size between the notch and the bottom is too small, resulting in the welded part 601 being easily disengaged from the connecting groove 501, causing the insulating pad 600 to be easily separated from the sealing plate 500. At the same time, it is also prevented that the difference in size between the notch and the bottom is too large, resulting in the molten material forming the welded part 601 during the thermal fusion process being difficult to fill the connecting groove 501 completely, thereby reducing the bonding area between the welded part 601 and the groove wall of the connecting groove 501, weakening the bonding strength, and making the insulating pad 600 easily separated from the sealing plate 500.

[0046] In one embodiment, the distance between the upper side surface of the sealing plate 500 and the bottom of the connecting groove 501 is t, and 1.5 mm ≥ t ≥ 0.2 mm.

[0047] Specifically, the distance between the upper side surface of the sealing plate 500 and the bottom of the connecting groove 501 is the thickness of the sealing plate 500 at the position of the connecting groove 501.

[0048] In this embodiment, the staff controls the distance between the bottom of the connecting groove 501 and the upper side surface of the sealing plate 500, so as to reserve enough depth for the connecting groove 501, and then make the sealing plate 500 and the insulating pad 600 have sufficient bonding strength. At the same time, it also avoids the situation that the thickness of the sealing plate 500 at the position of the connecting groove 501 is too small, resulting in weak structural strength, easy breakage, and electrolyte leakage of the battery cell, etc., affecting the battery quality, and improves the reliability of the battery cell.

[0049] In one embodiment, the depth of the connecting groove 501 is H, and 1.2 mm ≥ H ≥ 0.3 mm.

[0050] Specifically, the depth of the connecting groove 501 refers to the distance between the notch of the connecting groove 501 and the bottom of the connecting groove 501 in the thickness direction of the sealing plate 500.

[0051] In this embodiment, the staff controls the depth of the connecting groove 501 to avoid the situation that the connection strength between the sealing plate 500 and the insulating pad 600 is weak due to the too small depth of the connecting groove 501. At the same time, it also avoids the situation that when the sealing plate 500 and the insulating pad 600 are heat-melt connected, the molten material cannot fully fill the connecting groove 501 due to the too large depth of the connecting groove 501, which affects the connection strength. In addition, it also avoids the situation that the depth of the connecting groove 501 is set too large, resulting in the too thin thickness of the sealing plate 500 at the position of the connecting groove 501, which affects the structural strength of the sealing plate 500.

[0052] In one embodiment, please refer to Figures 2 to 4 , there are multiple connecting grooves 501, and the connecting grooves 501 are arranged in a matrix on the sealing plate 500, or the connecting grooves 501 are arranged linearly on the sealing plate 500.

[0053] Specifically, when the connecting grooves 501 are arranged in a matrix on the sealing plate 500 or the connecting grooves 501 are arranged linearly on the sealing plate 500, the connecting grooves 501 can be relatively evenly distributed on the sealing plate 500, so as to form evenly distributed bonding points.

[0054] In this embodiment, by arranging the connecting grooves 501 in a matrix or linearly on the sealing plate 500, when the sealing plate 500 and the insulating pad 600 are heat-melt connected, while the molten material combines with the sealing plate 500 to form a fixing method similar to integral bonding, a more firm bonding point is formed between the sealing plate 500 and the insulating pad 600 at the positions of the connecting grooves 501 and the welding part 601. Multiple bonding points are distributed on the plate surface of the sealing plate 500 and act on the insulating pad 600 together, which can effectively avoid the situation that the insulating pad 600 is partially separated from the sealing plate 500, and further improves the bonding stability between the sealing plate 500 and the insulating pad 600.

[0055] In one embodiment, please refer to Figure 1 and Figures 5 to 8 , a pair of pole columns 203 are provided on the cover plate 200, the pole columns 203 penetrate through the cover plate 200, one end of the connecting piece 300 abuts against the bottom end of the pole column 203, the pole ear 401 extends towards the cover plate 200 and bends towards the connecting piece 300, and the bent part of the pole ear 401 abuts against the upper surface of the connecting piece 300.

[0056] In this embodiment, one end of the connecting piece 300 on the lower side of the cover plate 200 is located at the lower end of the corresponding pole column 203 and is connected to the pole column 203, while the other end extends laterally to a position opposite to the through groove 201, facilitating connection with the tab 401, enabling the staff to conveniently perform welding operations on the tab 401 and the connecting piece 300 through the position of the through groove 201. Since the tab 401 led out from the electrode group 400 is disposed opposite to the corresponding through groove 201 and is located laterally of the corresponding pole column 203, when electrically connecting the tab 401 to the pole column 203, the connecting piece 300 can be arranged in an approximately flat plate-like structure, thus saving the longitudinal space inside the housing 100. Additionally, since the connecting piece 300 is arranged in an approximately flat plate-like structure, when connecting the tab 401 to the connecting piece 300, the tab 401 has more sufficient bending space, facilitating control of the bending angle of the tab 401 to enhance the connection stability between the tab 401 and the connecting piece 300, and can also further reduce the occupation of the longitudinal space inside the housing 100.

[0057] In one embodiment, a connection hole 202 is provided at a position on the cover plate 200 corresponding to the pole column 203. The pole column 203 passes through the connection hole 202 and is connected to the cover plate 200. A sealing ring 703 and a first insulating member 701 are provided inside the connection hole 202. The sealing ring 703 surrounds the circumference of the pole column 203 and separates the pole column 203 from the cover plate 200. The first insulating member 701 extends in the direction of the through groove 201 parallel to the plate surface of the cover plate 200 and separates the connecting piece 300 from the cover plate 200.

[0058] In this embodiment, by providing the sealing ring 703 and the first insulating member 701, the sealing ring 703 is arranged around the pole column 203, improving the sealing performance at the connection hole 202, avoiding the situation of electrolyte leakage from the battery cell and external liquid entering the battery cell, and at the same time separating the pole column 203 from the cover plate 200 to avoid short circuit. The first insulating member 701 is arranged on the upper side of the connecting piece 300, separating the connecting piece 300 from the cover plate 200 and the sealing plate 500, avoiding short circuit between the connecting piece 300 and the cover plate 200 and the sealing plate 500, resulting in the leakage of the housing 100, and improving the reliability of the battery cell.

[0059] In one embodiment, a second insulating member 702 is provided on the side of the cover plate 200 facing the inside of the housing 100. The second insulating member 702 is located between a pair of through grooves 201. The second insulating member 702 extends in the direction of the two through grooves 201 and separates the connecting piece 300 from the cover plate 200.

[0060] In this embodiment, by providing a second insulating member 702 at a position between two through slots 201 on the cover plate 200, the portion of the cover plate 200 between the two through slots 201 is separated from one end of the connecting piece 300 extending towards the middle of the cover plate 200, enabling the connecting piece 300 to extend to the side of the through slot 201 close to the middle of the cover plate 200. Thus, while having sufficient length, it will not be short-circuited with the cover plate 200, effectively avoiding the situation of the housing 100 leaking electricity. Additionally, since the connecting piece 300 has sufficient length, it also provides sufficient space for the connection between the connecting piece 300 and the tab 401, reducing the situation where poor contact between the tab 401 and the connecting piece 300 affects the performance of the battery cell.

[0061] In one embodiment, the cover plate 200 is provided with a liquid injection hole 204 penetrating the cover plate 200 in the thickness direction, and the liquid injection hole 204 is provided between a pair of through slots 201.

[0062] In this embodiment, by providing the liquid injection hole 204 on the cover plate 200, the liquid injection hole 204 is located above the battery cell. Thus, during the battery cell manufacturing process, processing operations such as the assembly of the electrode group 400, the welding of the cover plate 200, the bending of the tab 401, the welding of the tab 401 and the connecting piece 300, the welding of the sealing plate 500 and the connecting piece 300, and the liquid injection processing of the battery cell can all be carried out from the same side of the housing 100, simplifying the assembly steps and facilitating the reduction of the difficulty of the automated design of the battery cell assembly line.

[0063] According to an embodiment of the present invention, on the other hand, a battery pack is also provided, including a plurality of the above-mentioned battery cells.

[0064] In this embodiment, the battery cell group in the battery pack is composed of the above-mentioned battery cells, thereby improving the reliability of the battery pack. At the same time, the sealing plate 500 and the insulating pad 600 have reliable connection strength, greatly reducing the situation of leakage after the battery cells are assembled, improving the product reliability, and enhancing the production efficiency of the battery pack.

[0065] 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 cell, characterized in that, Comprising: A housing having an opening on its upper side; A cover plate, the peripheral contour of which is adapted to the contour of the opening, and a pair of through grooves are formed in the cover plate; A pair of connecting pieces, provided on the lower side of the cover plate, one end of the connecting piece extending to the lower side of the through groove and being disposed opposite to the through groove; A pole group, provided in the housing, two sets of pole lugs being provided at one end of the pole group, and the two sets of pole lugs being respectively disposed in one-to-one correspondence with a pair of through grooves; A pair of sealing plates, the peripheral contours of which are respectively adapted to the corresponding through grooves and are welded to the groove walls of the through grooves. At least one connecting groove is provided on the lower side plate surface of the sealing plate, and the notch size of the connecting groove is larger than the bottom size; A pair of insulating pads, provided on the lower side of the corresponding sealing plate, the insulating pads being heat-melted and connected to the sealing plate to form welding parts having the same number as the connecting grooves, and the welding parts being adapted to the connecting grooves.

2. The battery cell according to claim 1, characterized in that, The connecting groove is a frustum-shaped groove, the notch diameter of the connecting groove is d, the bottom diameter of the connecting groove is D, and D - d ≥ 0.3 mm is satisfied.

3. The battery cell according to claim 2, wherein, The distance between the upper side plate surface of the sealing plate and the bottom of the connecting groove is t, and 1.5 mm ≥ t ≥ 0.2 mm.

4. The battery cell according to claim 2 or 3, characterized in that, The depth of the connecting groove is H, and 1.2 mm ≥ H ≥ 0.3 mm.

5. The battery cell according to claim 4, wherein, A plurality of the connecting grooves are provided, and the connecting grooves are arranged in a matrix on the sealing plate or are arranged linearly on the sealing plate.

6. The battery cell according to claim 4, wherein, A pair of pole columns are provided on the cover plate, the pole columns penetrating through the cover plate. One end of the connecting piece abuts against the bottom end of the pole column, the pole lug extends towards the cover plate and bends towards the connecting piece, and the bent part of the pole lug abuts against the upper surface of the connecting piece.

7. The battery cell according to claim 6, characterized in that, A connecting hole is provided at the position corresponding to the pole column on the cover plate, the pole column passes through the connecting hole and is connected to the cover plate. A sealing ring and a first insulating member are provided inside the connecting hole. The sealing ring surrounds the periphery of the pole column and separates the pole column from the cover plate. The first insulating member extends in the direction of the through groove parallel to the plate surface of the cover plate and separates the connecting piece from the cover plate.

8. The battery cell according to claim 7, characterized in that, A second insulating member is provided on the side of the cover plate facing the inside of the housing, the second insulating member being located between a pair of the through grooves, and the second insulating member extends in the direction of the two through grooves and separates the connecting piece from the cover plate.

9. The battery cell according to claim 8, wherein, A liquid injection hole penetrating through the cover plate in the thickness direction is provided on the cover plate, and the liquid injection hole is provided between a pair of the through grooves.

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

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