A pole welding structure of a square steel shell battery and the battery

Abstract

The present invention belongs to the technical field of battery production and manufacturing, and particularly relates to a pole column welding structure for a square steel shell battery, comprising a first pole column (1); a second pole column (2); a through hole (3) or a blind hole (4) matching the second pole column (2) is arranged at the bottom of the first pole column (1), the second pole column (2) passes through the through hole (3) or the blind hole (4) and is fixedly connected to the first pole column (1), an extension part (21) is arranged at the bottom of the second pole column (2), and the extension part (21) is fixedly connected to the pole ear of the battery. The present invention can prevent the pole ear from being damaged due to multiple bends during internal welding of the pole ear, resulting in the fracture of the thin foil material, which helps to improve the quality of the battery, reduce the defective rate, and enhance the efficiency. In addition, the present invention also discloses a battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery production and manufacturing, and particularly relates to a pole column welding structure and a battery for a square steel shell battery. Background Art

[0002] Nowadays, countries are vigorously developing green and efficient secondary batteries. As a new type of secondary battery, lithium-ion batteries have the advantages of high energy density, high power density, high working voltage, light weight, small size, long cycle life, good safety, and environmental friendliness, and have broad application prospects in portable electrical appliances, electric tools, large-scale energy storage, electric vehicle power sources, etc. For a small steel shell square battery, the material of the positive pole column is metal aluminum, which is riveted on the steel shell, and the electrode tab of the battery cell is welded to the pole column by laser welding.

[0003] There are two types of laser welding directions: external welding and internal welding. For external welding, usually the pole column needs to be made thin so that the laser for external welding can penetrate the thin pole column to weld the electrode tab to the pole column. This method can achieve external welding, but this structure requires welding a sealing piece outside the weld mark to prevent the welding part at the electrode tab welding position from being welded through and causing the battery to leak and fail, which increases the process cost and material cost. Another method is internal welding, welding from the inside of the shell. With this welding method, the thickness of the pole column can be made very thick to prevent the pole column from being welded through during welding. However, during welding, it is necessary to first use a laser to weld the electrode tab to the pole column from the inside, and then fold the battery cell into the shell. The electrode tab group is prone to being pulled during the shell insertion process and breaking, resulting in electrical connection failure. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a pole column welding structure for a square steel shell battery, aiming at the deficiencies of the prior art, which can prevent the electrode tab from being damaged due to multiple bends during internal welding of the electrode tab, resulting in the breakage of the thin foil material, helping to improve the quality of the battery, reduce the defective rate, and increase the efficiency.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A pole column welding structure for a square steel shell battery includes a first pole column; a second pole column; a through hole or a blind hole matching the second pole column is provided at the bottom of the first pole column, the second pole column passes through the through hole or the blind hole and is fixedly connected to the first pole column, an extension part is provided at the bottom of the second pole column, and the extension part is fixedly connected to the electrode tab of the battery.

[0007] Preferably, the extension part is provided around the bottom of the second pole column, and the second pole column and the extension part form a T-shaped structure.

[0008] Preferably, the first pole column and the second pole column are fixedly connected by laser welding, and the welding method is seam welding or penetration welding.

[0009] Preferably, the end face of the second pole column is circular, square or rectangular, and the end face of the extension part is circular, oval, square or rectangular.

[0010] Preferably, the outer diameter of the second pole column is equal to the inner diameter of the through hole or blind hole.

[0011] Preferably, a recess is provided on the outer wall of the first pole column. The recess surrounds the outer wall of the first pole column and is used for embedding a seal connected to the side wall of the housing.

[0012] A second object of the present invention is to provide a battery, including a cover plate; a housing provided with an opening; an electric core accommodated in the housing; and a pole column welding structure of the square steel shell battery as described above. The pole column welding structure is fixedly connected to the side wall of the housing, and the cover plate is fixed to the opening. The cover plate is used to enclose the electric core in the housing.

[0013] Preferably, the electric core includes a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are stacked or wound to form the electric core, and pole tabs are provided on the end face of the electric core.

[0014] Preferably, a step is provided at the edge of the opening or the cover plate, and the housing and the cover plate are fixedly connected by laser welding.

[0015] Preferably, a liquid injection port is provided on the side wall of the housing, a sealing piece is installed at the liquid injection port, and an explosion-proof notch is provided on the cover plate.

[0016] The beneficial effects of the present invention are as follows. The present invention includes a first pole column and a second pole column. A through hole or a blind hole matching the second pole column is provided at the bottom of the first pole column. The second pole column passes through the through hole or the blind hole and is fixedly connected to the first pole column. An extension part is provided at the bottom of the second pole column, and the extension part is fixedly connected to the tab of the battery. Since in the existing structure during welding, it is necessary to first use a laser to weld the tab to the pole column from the inside and then fold the battery core into the shell, the tab group is prone to being pulled during the shelling process, resulting in breakage and causing electrical connection failure. Therefore, the pole column is divided into two parts. A sealing and insulating material is sleeved outside the first pole column, and a through hole or a blind hole is provided in the middle of the first pole column. The second pole column can be placed into the through hole or the blind hole of the first pole column. Moreover, by adding the extension part, it is convenient to laser-weld the second pole column and the tab group together, that is, first laser-weld the second pole column and the tab group together and then put them into the shell, reducing the number of bends of the tab and eliminating the need for folding into the shell, preventing the tab from being damaged due to multiple bends during internal tab welding and causing the thin foil to break. Among them, the first pole column and the second pole column are welded by external laser, and the welding position is at the top of the pole column, eliminating the need to weld a sealing piece outside the weld mark to prevent the welding part at the tab welding position from being welded through and causing the battery to leak and fail, which helps to reduce production costs. The present invention can prevent the tab from being damaged due to multiple bends during internal tab welding and causing the thin foil to break, which helps to improve the quality of the battery, reduce the defective rate, and increase the efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The features, advantages, and technical effects of the exemplary embodiments of the present invention will be described below with reference to the drawings.

[0018] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention.

[0019] Figure 2 It is an exploded schematic diagram of Embodiment 1 of the present invention.

[0020] Figure 3 It is a schematic diagram of the battery assembled in Embodiment 1 of the present invention.

[0021] Figure 4 It is a schematic diagram of the connection between the cover plate and the housing in Embodiment 1 of the present invention.

[0022] Figure 5 It is a schematic diagram of the connection between the cover plate and the housing in Embodiment 2 of the present invention.

[0023] Figure 6 It is a schematic structural diagram of Embodiment 3 of the present invention.

[0024] Figure 7 It is an exploded schematic diagram of Embodiment 3 of the present invention.

[0025] Figure 8 Schematic diagram of the battery assembled in Embodiment 3 of the present invention.

[0026] Figure 9 Schematic diagram of the connection between the cover plate and the housing in Embodiment 3 of the present invention.

[0027] Figure 10 Schematic diagram of the connection between the cover plate and the housing in Embodiment 4 of the present invention.

[0028] Figure 11 Schematic diagram of the installation of the cover plate and the housing in Embodiment 1 of the present invention.

[0029] Figure 12 Schematic diagram of the installation of the cover plate and the housing in Embodiment 5 of the present invention.

[0030] Figure 13 Schematic diagram of the installation of the cover plate and the housing in Embodiment 6 of the present invention.

[0031] Among them, the reference numerals are explained as follows:

[0032] 1 - First pole; 11 - Recess;

[0033] 2 - Second pole; 21 - Extension;

[0034] 3 - Through hole;

[0035] 4 - Blind hole;

[0036] 5 - Seal;

[0037] 6 - Cover plate; 61 - Explosion-proof notch;

[0038] 7 - Housing; 71 - Liquid injection port; 711 - Sealing sheet; 72 - Welding sheet;

[0039] 8 - Step. Detailed implementation manners

[0040] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" is an open-ended term and should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range, and those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0041] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0042] In the invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The following will further elaborate on the present invention in conjunction with the attached Figures 1 to 13 but it does not limit the present invention.

[0044] Embodiment 1

[0045] The following will describe Embodiment 1 in conjunction with the attached Figures 1 to 4 Description of Embodiment 1

[0046] The pole column welding structure of a square steel shell battery includes a first pole column 1; a second pole column 2; a through hole 3 matching the second pole column 2 is provided at the bottom of the first pole column 1, the second pole column 2 passes through the through hole 3 and is fixedly connected to the first pole column 1, and an extension part 21 is provided at the bottom of the second pole column 2, and the extension part 21 is fixedly connected to the pole ear group.

[0047] In the existing structure welding, it is necessary to first use laser to weld the pole ear to the pole column from the inside, and then turn over the battery core into the shell. The pole ear group is prone to be pulled during the shelling process, resulting in fracture and causing electrical connection failure. Therefore, the pole column is divided into two parts. The outer ring of the first pole column 1 is sealed with insulating material, and a through hole 3 is provided in the middle of the first pole column 1. The second pole column 2 can be placed into the through hole 3 of the first pole column 1. Moreover, by adding the extension part 21, it is convenient to laser-weld the second pole column 2 and the pole ear group together, that is, first laser-weld the second pole column 2 and the pole ear group together, and then put them into the shell, reducing the number of bends of the pole ear and eliminating the need for turning over and shelling, preventing the pole ear from being damaged due to multiple bends during internal welding of the pole ear and resulting in the fracture of the thin foil. Among them, the first pole column 1 and the second pole column 2 are welded by external laser, and the welding position is at the top of the pole column, eliminating the need to weld a sealing piece outside the welding mark to prevent the welding part at the pole ear welding point from being penetrated and causing battery leakage failure, which helps to reduce production costs.

[0048] In the pole column welding structure of the square steel shell battery according to the present invention, the extension part 21 is arranged around the bottom of the second pole column 2, and the second pole column 2 and the extension part 21 form a T-shaped structure. Specifically, the aluminum pole ear is laser-welded on the second pole column 2 of the T-shaped structure, and the welding point of the pole ear is the large end face of the T-shaped second pole column 2.

[0049] In the pole welding structure of the square steel shell battery according to the present invention, the first pole 1 and the second pole 2 are fixedly connected by laser welding, and the welding method is seam welding or penetration welding.

[0050] In the pole welding structure of the square steel shell battery according to the present invention, the end face of the second pole 2 is circular, square or rectangular, and the end face of the extension part 21 is circular, oval, square or rectangular. Specifically, the second pole 2 is divided into two parts. One part penetrates through the through hole 3, and the end face of this part is smaller, and it can adopt the shape of a perfect circle, square or rectangle, preferably a perfect circle. The other part is exposed below the first pole 1, and the end face of this part is larger, and it can adopt shapes such as a perfect circle, square or rectangle.

[0051] In the pole welding structure of the square steel shell battery according to the present invention, the outer diameter of the second pole 2 is equal to the inner diameter of the through hole 3. Through precision machining, the gap between the two can be reduced to make them closely assembled. At the same time, by using the external laser welding method to weld the first pole 1 and the second pole 2 together, it helps to improve the welding effect.

[0052] In the pole welding structure of the square steel shell battery according to the present invention, a concave part 11 is provided on the outer wall of the first pole 1. The concave part 11 is arranged around the outer wall of the first pole 1. The concave part 11 is used to embed the seal 5 connected to the side wall of the housing 7. In this embodiment, the concave part 11 plays a role in limiting the seal 5 to prevent the seal 5 from shifting or shaking. Among them, the overall external shape of the first pole 1 is an I-shaped structure. The seal 5 plays a role in insulating the first pole 1 and the cover plate 6, and at the same time, the first pole 1 is stuck in the installation opening of the cover plate 6.

[0053] A battery, including a cover plate 6; a housing 7 provided with an opening; an electric core accommodated in the housing 7; and the pole welding structure of the square steel shell battery as described above, the pole welding structure is fixedly connected to the side wall of the housing 7, and the cover plate 6 is fixed to the opening, and the cover plate 6 is used to enclose the electric core in the housing 7.

[0054] In the pole welding structure of the square steel shell battery according to the present invention, the electric core includes a positive electrode plate, a separator and a negative electrode plate. The positive electrode plate, the separator and the negative electrode plate are wound to form the electric core, and pole tabs are provided on the end face of the electric core. Specifically, the positive electrode plate, the negative electrode plate and the separator are wound to form a core, and the positive and negative pole tabs are led out from the end face of the core. The positive pole tab and the negative pole tab are an aluminum strip and a nickel strip (copper strip, copper-nickel plated strip) respectively, and are welded to the empty foil on the corresponding electrode plate by ultrasonic welding. Insulation treatment is carried out on the non-welding points of the aluminum strip, and the treatment methods include but are not limited to heat-compounding PP glue, insulating adhesive paper, coating insulating glue, etc.

[0055] In the pole welding structure of the square steel shell battery according to the present invention, a step 8 is provided at the edge of the cover plate 6, and the shell 7 and the cover plate 6 are fixedly connected by laser welding. Specifically, the opening is provided with a step 8, which can be positioned in cooperation with the cover plate 6, and the shell 7 and the cover plate 6 are welded together by laser. Among them, the cross-sectional shape of the step 8 can be designed as a square, such as a square, a rectangle or other irregular shapes. The step 8 is provided at the edge of the cover plate 6, and the thickness of the step 8 is slightly less than the thickness of the main body of the cover plate 6, forming a structure similar to a step with the main body of the cover plate 6, so that the main body of the cover plate 6 can be directly embedded into the opening. During welding, with a little pressure, it can ensure that the two components are in close contact, which helps to reduce the gap between them and will not cause displacement resulting in misalignment of the edges, making the battery have good sealing performance.

[0056] In the pole welding structure of the square steel shell battery according to the present invention, a liquid injection port 71 and a welding piece 72 are provided on the side wall of the shell 7. A sealing piece 711 is installed on the liquid injection port 71, and an explosion-proof notch 61 is provided on the cover plate 6. The welding piece 72 is connected to the shell 7 and can be used as the negative electrode. Among them, a semi-circle is first laser-etched on the cover plate 6 as the explosion-proof notch 61, which has the function of explosion-proof. When the battery has a safety problem, a large amount of gas is generated, resulting in a sharp increase in internal pressure. The pressure will break through the notch here to discharge the pressure, acting as a safety valve to prevent further thermal runaway of the battery. A liquid injection port 71 is provided on the side wall of the shell 7. After injection, it is sealed with a sealing nail. After formation, the sealing nail is removed, and the gas is exhausted. By using the laser welding method, a circular stainless steel sheet is welded on the liquid injection port 71 to seal the liquid injection hole. Then, after subsequent injection, it is left standing, formed, capacity-divided, and the battery is obtained through OCV testing.

[0057] The working principle of the present invention is:

[0058] The battery core is placed into the shell 7, and the second pole 2 is synchronously inserted into the through hole 3 of the first pole 1. Among them, the first pole 1 is a hollow structure and is clamped by a fixture to ensure close contact between the first pole 1 and the second pole 2. Outside the shell 7, the gap between the first pole 1 and the second pole 2 is welded together by laser. Since the laser welding position is fusion welding, the welding effect can be ensured. The pole ear is clamped and pressed on the shell 7 by a fixture and is also welded to the shell 7 by the external laser welding method.

[0059] Embodiment 2

[0060] The positive electrode plate, the negative electrode plate, and the separator are stacked by laminating to form a stacked core, and the positive and negative pole ear groups are led out from the end face of the wound core.

[0061] The positive and negative tab groups are each welded together as tabs. The positive tab group can also be transferred to an aluminum strip, and the copper tab group can be transferred to a nickel strip, a copper strip, or a copper-nickel plated strip. Insulation treatment is performed on the non-welding points of the aluminum tabs. The treatment methods include but are not limited to heat-composite PP glue, insulating adhesive paper, coating insulating glue, etc.

[0062] The aluminum tab is laser-welded to the second pole column 2 of the T-shaped structure. The welding point of the tab is the large end face of the T-shaped second pole column 2.

[0063] An outer sleeve of the first pole column 1 is sealed with an insulating material, and there is a circular through-hole 3 in the middle. The second pole column 2 is a cylinder with a T-shaped structure and can be placed in the through-hole 3 of the first pole column 1. Control the machining accuracy of the circular hole of the first pole column 1 and the small cylinder of the second column 2 to reduce the gap between the two and make them closely assembled. Adopt an external laser welding method to weld the first pole column and the second pole column together to improve the welding effect. The second pole column 2 and the tab group can be laser-welded together first and then put into the shell, reducing the number of bends of the tabs and eliminating the need to fold them into the shell.

[0064] Put the battery cell into the shell 7, and synchronously embed the second pole column 2 into the through-hole 3 of the first pole column 1. The first pole column 1 is a hollow structure and is clamped by a fixture to ensure close contact between the first pole column 1 and the second pole column 2. Outside the shell 7, laser is used to weld the gap between the first pole column 1 and the second pole column 2 together. Since the laser welding position is fusion welding, the welding effect can be guaranteed. The negative tab is clamped and pressed against the outer shell by a fixture and is also welded to the shell by an external laser welding method.

[0065] Steps 8 are provided at the edges of both the opening and the cover plate 6 for positioning in cooperation with the cover plate 6. The shell 7 and the cover plate 6 are welded together by laser. Among them, a semi-circle is first laser-etched on the cover plate 6 as an explosion-proof mark 61, which has the function of explosion-proof. When the battery has a safety problem and a large amount of gas is generated, resulting in a sharp increase in internal pressure, the pressure will break through the mark here to discharge the pressure, acting as a safety valve to prevent further thermal runaway of the battery.

[0066] Specifically, steps 8 are provided at the edges of both the opening and the cover plate 6. The cross-sectional shape of the step 8 can be designed as a square, such as a square, a rectangle, a triangle, or other irregular shapes. The shapes of the steps 8 of the opening and the cover plate 6 cooperate with each other, facilitating positioning and laser welding. The welding surface between the cover plate 6 and the shell 7 is horizontal, and the weld seam is also horizontal, which can eliminate the influence of gravity, make the weld seam uniform, and have good welding quality, improving the welding effect.

[0067] A liquid injection port 71 is provided on the side wall of the shell 7. After injection, it is sealed with a sealing nail. After formation, the sealing nail is removed and the gas is exhausted. A circular stainless steel sheet is welded to the liquid injection port 71 by laser to seal the liquid injection hole.

[0068] After subsequent liquid injection and static settlement, formation, grading, OCV testing, etc., the battery is manufactured.

[0069] Embodiment 3

[0070] The positive electrode plate, negative electrode plate, and separator are wound to form a core, and the positive and negative electrode tabs are led out from the end face of the core.

[0071] The positive and negative electrode tabs are aluminum strips and nickel strips (copper strips, nickel-plated copper strips) respectively, and are welded to the empty foils on the corresponding electrode plates by ultrasonic welding. Insulation treatment is carried out on the non-welded points of the aluminum strip, and the treatment methods include but are not limited to thermal compounding of PP glue, insulating adhesive paper, coating insulating glue, etc.

[0072] The aluminum electrode tab is laser-welded to the second pole column 2 of the T-shaped structure, and the welding point of the electrode tab is the large end face of the T-shaped second pole column 2.

[0073] The first pole column 1 is hollow inside, and the hollow part is a cylinder. The inner bottom to be welded is made very thin. The second cylinder 2 is a cylinder of T-shaped structure. The small cylinder of the second cylinder 2 can be placed inside the hollow part of the first pole column 1, and the two fit tightly. The two components are welded by external laser. Since the inner part is a small cylinder with a certain thickness, at most the inner wall bottom of the first cylinder 1 can be welded through, and there is no need to worry about the liquid leakage due to the penetration of the welding mark and the inside. The second pole column and the electrode tab group can be laser-welded together first and then put into the shell, reducing the number of bends of the electrode tab and eliminating the need for folding and inserting into the shell.

[0074] The battery cell is placed into the shell 7, and the second pole column 2 is synchronously inserted into the blind hole 4 of the first pole column 1. The first pole column 1 is a hollow structure inside and is clamped by a fixture to ensure that the small end face of the T-shaped second pole column 2 is in close contact with the inner wall bottom of the first pole column 1. Outside the shell 7, the inner wall bottom surface of the first pole column 1 and the small end face of the second pole column 2 are welded together by laser. Since the bottom of the first pole column 1 can be made thin and the laser can penetrate, the first pole column 1 and the second pole column 2 are welded together. Since the second pole column 2 is very thick, even if the first pole column 1 is welded through, the second pole column 2 will not be welded through, thus ensuring the welding tightness. The negative electrode tab is clamped and pressed tightly on the outer shell by a fixture and is also welded to the shell 7 by external laser welding.

[0075] The opening of the shell 7 is provided with a step 8, which is matched with the cover plate 6 for positioning, and the shell 7 and the cover plate 6 are welded together by laser. Among them, the cover plate 6 is first laser-etched with a semi-circle as an explosion-proof mark 61, which has the function of explosion-proof. When the battery has a safety problem and generates a large amount of gas, resulting in a sharp increase in internal pressure, the pressure will break through the mark here to discharge the pressure, acting as a safety valve to prevent further thermal runaway of the battery.

[0076] Specifically, the opening is provided with a step 8. The cross-sectional shape of the step 8 can be designed as a square shape, such as a square, a rectangle, or other irregular shapes. The step 8 is provided at the edge of the opening. The thickness of the step 8 is slightly less than the thickness of the side of the opening, forming a structure similar to a step with the edge of the opening, so that the cover plate 6 can be directly embedded into the opening. During welding, with a little pressure, it can ensure that the two components are in close contact, which helps to reduce the gap between them and will not be displaced to cause the edges not to align, making the battery have good sealing performance.

[0077] A liquid injection port 71 is provided on the side wall of the housing 7. After injecting the liquid, it is sealed with a sealing nail. After formation, the sealing nail is removed and the air is exhausted. A circular stainless steel sheet is welded on the liquid injection port 71 by laser welding to seal the liquid injection hole.

[0078] After subsequent liquid injection, standing, formation, grading, OCV testing, etc., the battery is manufactured.

[0079] Embodiment 4

[0080] The positive electrode sheet, the negative electrode sheet, and the separator are stacked by laminating to form an electrode core, and the positive and negative electrode tab groups are led out from the end face of the wound core.

[0081] The positive and negative electrode tab groups are welded together as tabs respectively. Alternatively, the positive electrode tab group can be transferred to an aluminum strip, and the copper electrode tab group can be transferred to a nickel strip, a copper strip, or a copper-nickel plated strip. Insulation treatment is performed on the non-welding points of the aluminum tabs. The treatment methods include but are not limited to heat-composite PP glue, insulating adhesive paper, coating insulating glue, etc.

[0082] The aluminum tab is laser welded to the second pole column 2 of the T-shaped structure, and the welding point of the tab is the large end face of the T-shaped second pole column 2.

[0083] The first pole column 1 is hollow inside, and the hollow part is a cylinder. The inner bottom for welding is made very thin. The second column 2 is a cylinder of T-shaped structure. The small cylinder of the second column 2 can be placed into the inner hollow of the first pole column 1, and the two fit tightly. The two components are welded by external laser welding. Since the inside is a small cylinder with a certain thickness, at most the inner wall bottom of the first column 1 can be welded through, and there is no need to worry about the welding mark and the inside being penetrated to cause liquid leakage. The second pole column 2 and the tab group can be laser welded together first and then put into the shell, reducing the number of bends of the tabs and not requiring folding into the shell.

[0084] Place the battery cell into the housing 7, and synchronously embed the second pole column 2 into the blind hole 4 of the first pole column 1. The first pole column 1 has a hollow internal structure and is clamped by a fixture to ensure that the small end face of the T-shaped second pole column 2 is in close contact with the bottom of the inner wall of the first pole column 1. Outside the housing 7, use a laser to weld the bottom surface of the inner wall of the first pole column 1 and the small end face of the second pole column 2 together. Since the bottom of the first pole column 1 can be made thin and the laser can penetrate, the first pole column 1 and the second pole column 2 are welded together. Since the second pole column 2 is very thick, even if the first pole column 1 is welded through, the second pole column 2 will not be welded through, thus ensuring the welding tightness. The negative electrode tab is clamped and pressed tightly on the outer shell by a fixture, and is also welded to the housing 7 by an external laser welding method.

[0085] The opening of the housing 7 is provided with a step 8, which is positioned in cooperation with the cover plate 6, and the housing 7 and the cover plate 6 are welded together by a laser. Among them, the cover plate 6 is first laser-etched with a semicircle as an explosion-proof notch 61, which has the function of explosion-proof. When the battery has a safety problem and a large amount of gas is generated, resulting in a sharp increase in the internal pressure, the pressure will break through this notch here to discharge the pressure, acting as a safety valve to prevent further thermal runaway of the battery.

[0086] Specifically, the cross-sectional shape of the step 8 is designed as a triangle.

[0087] The side wall of the housing 7 is provided with a liquid injection port 71, which is sealed with a sealing nail after injection. After formation, the sealing nail is removed, the gas is exhausted, and a circular stainless steel sheet is welded on the liquid injection port 71 by laser to seal the liquid injection hole.

[0088] After subsequent injection, standing, formation, grading, OCV testing, etc., the battery is manufactured.

[0089] Embodiment Five

[0090] In this embodiment, the cover plate 6 is located on one of the side walls of the housing 7, and a pole column welding structure, a liquid injection port 71, and a welding piece 72 are provided on the cover plate 6.

[0091] Embodiment Six

[0092] In this embodiment, the cover plate 6 is located on one of the side walls of the housing 7, and there are no components on the cover plate 6. The pole column welding structure, the liquid injection port 71, and the welding piece 72 are all located on the other side wall of the housing 7.

[0093] Based on the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains are also able to make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the above specific embodiments, and any obvious improvements, substitutions or variations made by those skilled in the art on the basis of the present invention all fall within the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A pole welding structure for a square steel shell battery, characterized in that, it includes: a first pole (1); a second pole (2); a through hole (3) or a blind hole (4) matching the second pole (2) is provided at the bottom of the first pole (1), the second pole (2) passes through the through hole (3) or the blind hole (4) and is fixedly connected to the first pole (1), an extension part (21) is provided at the bottom of the second pole (2), and the extension part (21) is fixedly connected to the pole ear of the battery; wherein, the extension part (21) is arranged around the bottom of the second pole (2), and the second pole (2) and the extension part (21) form a T-shaped structure; a concave part (11) is provided on the outer wall of the first pole (1), the concave part (11) is arranged around the outer wall of the first pole (1), and the concave part (11) is used for embedding a seal (5) connected to the side wall of the housing (7).

2. A pole welding structure for a square steel shell battery according to claim 1, characterized in that: the first pole (1) and the second pole (2) are fixedly connected by laser welding, and the welding method is seam welding or penetration welding.

3. A pole welding structure for a square steel shell battery according to claim 1, characterized in that: the end face of the second pole (2) is circular, square or rectangular, and the end face of the extension part (21) is circular, oval, square or rectangular.

4. A pole welding structure for a square steel shell battery according to claim 1, characterized in that: the outer diameter of the second pole (2) is equal to the inner diameter of the through hole (3) or the blind hole (4).

5. A battery, characterized in that, it includes: a cover plate (6); a housing (7) provided with an opening; an electric core accommodated in the housing (7); and the pole welding structure for a square steel shell battery according to any one of claims 1-4, the pole welding structure is fixedly connected to the side wall of the housing (7), the cover plate (6) is fixed to the opening, and the cover plate (6) is used to enclose the electric core in the housing (7).

6. A battery according to claim 5, characterized in that: the electric core includes a positive electrode plate, a separator and a negative electrode plate, the positive electrode plate, the separator and the negative electrode plate are stacked or wound to form the electric core, and a pole ear is provided at the end face of the electric core.

7. A battery according to claim 5, characterized in that: a step (8) is provided at the edge of the opening or the cover plate (6), and the housing (7) and the cover plate (6) are fixedly connected by laser welding.

8. A battery according to claim 5, characterized in that: a liquid injection port (71) is provided on the side wall of the housing (7), a sealing piece (711) is installed at the liquid injection port (71), and an explosion-proof notch (61) is provided on the cover plate (6).

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