Battery cell, manufacturing method, and battery pack

Abstract

The application relates to the technical field of power batteries, in particular to a battery monomer, a manufacturing method and a battery pack, the battery monomer comprising a battery shell, an electric core, a busbar and a pole, the pole comprising an outer layer part and a core part, the outer layer part being wrapped around the outer periphery of the core part, the core part being protruded from the outer layer part at one end towards the busbar, the pole being arranged in the battery shell and being welded to the busbar, the outer layer part being sealingly welded to the busbar, the outer layer part being sealingly connected to a cover plate, the material of the outer layer part being different from that of the core part, the outer layer part and the busbar being sealingly welded, and a sealing weld being formed between the outer layer part and the busbar, the sealing weld permanently physically isolating the electrolyte in the battery monomer from the bonding surface between the core part and the outer layer part in the pole and the core part with a higher potential, so that the coexistence condition of the electrolyte and the dissimilar metal is eliminated, the risk of electrochemical corrosion in the pole is prevented, and the long-term safety and reliability of the battery are improved.

Description

Technical Field

[0001] This invention relates to the field of power battery technology, and in particular to a battery cell, manufacturing method, and battery pack. Background Technology

[0002] As a core component of new energy vehicles and energy storage systems, the performance, cost, safety, and reliability of power batteries are of paramount importance. The terminals serve as the key channels for energy input and output within a single battery cell. Currently, in related technologies, pure copper or pure aluminum are commonly used as terminal materials. Pure copper terminals have good conductivity but are expensive and dense, which is detrimental to improving battery energy density and cost control; while pure aluminum terminals are cheaper and lighter, their conductivity is inferior to copper.

[0003] A more prominent problem is that when multiple battery cells need to be connected in series and parallel via a busbar, the connection of the busbar becomes extremely complex if the battery cell terminals are not made of the same material (e.g., one terminal is copper and the other is aluminum). Typically, ultrasonic welding, mechanical pressing, or the addition of copper-aluminum transition plates are required. These methods suffer from drawbacks such as high connection resistance, poor long-term reliability, cumbersome processes, and high costs.

[0004] Furthermore, if there are dissimilar metals in the terminal or the connection interface, and there is an electrolyte passage, the two metals will form a galvanic cell in the electrolyte, which will cause the active metal (such as aluminum) to be corroded more quickly, seriously threatening the long-term safety and service life of the battery. Summary of the Invention

[0005] In one aspect, the present invention provides a battery cell; in another aspect, the present invention provides a method for manufacturing a battery cell; and in yet another aspect, the present invention provides a battery pack, the purpose of which is to solve the problem of easy corrosion of the terminals after the busbar is connected to terminals of different materials.

[0006] On one hand, the present invention provides a battery cell comprising:

[0007] A battery casing, the battery casing including a cover plate and a casing body, the casing body having an opening, and the cover plate disposed at the opening;

[0008] A battery cell, wherein the battery cell is disposed within the battery casing, the battery cell comprising a core body and a tab, the core body being connected to the tab;

[0009] A busbar is disposed inside the battery casing, the busbar is located between the battery cell and the cover plate, and the busbar is connected to the electrode tab;

[0010] The electrode post includes an outer layer and a core. The outer layer covers the outer periphery of the core. One end of the core protrudes from the outer layer and faces the busbar. The electrode post passes through the battery casing and is welded to the busbar. Both the outer layer and the core are welded to the busbar. The outer layer is sealed to the cover plate. The material of the outer layer is different from that of the core.

[0011] Based on the above technical solutions, optionally, one of the outer layer and the core may be made of copper or copper-aluminum alloy, and the other may be made of aluminum or aluminum alloy.

[0012] Based on the above technical solutions, optionally, the outer layer has a welding boss extending radially, the busbar has a mounting groove, and the welding boss is laser welded into the mounting groove; and / or,

[0013] The middle part of the busbar is welded to the outer layer and the core part by laser penetration welding.

[0014] Based on the above technical solutions, optionally, the diameter of the welding boss is the same as the diameter of the mounting groove, and the height of the welding boss is less than or equal to the depth of the mounting groove.

[0015] Based on the above technical solutions, optionally, the outer layer and the cover plate are encapsulated by injection molding, or the outer layer and the cover plate are sealed by welding, or a sealing ring is provided between the outer layer and the cover plate.

[0016] Based on the above technical solutions, optionally, the length of the protrusion of the end of the core facing the busbar is h, where h is 2-10mm.

[0017] Based on the above technical solutions, optionally, the middle part of the busbar is welded to the outer layer and the core part by laser penetration welding.

[0018] Based on the above technical solutions, optionally, the electrode post includes a first electrode post and a second electrode post, wherein the outer layer of the first electrode post has a groove at one end opposite to the busbar, and the core of the second electrode post protrudes from the outer layer at one end opposite to the busbar.

[0019] Secondly, the present invention provides a method for manufacturing a battery cell, for manufacturing a battery cell provided by any of the above-mentioned solutions, comprising the following steps:

[0020] S101. Manufacture a pole post and make one end of the core protrude from the mounting plane of the outer layer.

[0021] S102. Using a high-energy beam welding process, the welding boss is laser welded into the mounting groove of the busbar, and the outer layer and the bottom of the core are welded to the busbar through the weld.

[0022] S103. Connect the battery cell's tabs to the busbar.

[0023] S104. Install the battery cell into the battery casing, pass the terminal through the cover plate to seal it, and connect the cover plate to the casing.

[0024] S105. After drying, the battery is injected with electrolyte and formed, and then packaged.

[0025] Based on the above technical solutions, the laser power in the optional high-energy beam welding process can be 2-8KW, the welding speed can be 20-100mm / s, and the shielding gas can be nitrogen or helium.

[0026] On the other hand, the present invention provides a battery pack comprising the battery cells of any of the above-described embodiments.

[0027] Based on the above technical solutions, optionally, the material of the outer layer is the same as the material of the busbar.

[0028] The above technical solution has at least the following advantages or beneficial effects:

[0029] The electrode post passes through the battery casing and is welded to the busbar to achieve electrode-busbar connection. Since the outer layer covers the outer periphery of the core, the outer layer and the busbar are sealed by welding, and the welding between the outer layer and the busbar forms a sealed weld. This sealed weld permanently and physically isolates the electrolyte inside the battery cell from the interface between the core and the outer layer inside the electrode post, as well as the core with a higher potential. This eliminates the conditions for the electrolyte to coexist with dissimilar metals, thereby fundamentally preventing the risk of electrochemical corrosion inside the electrode post and greatly improving the long-term safety and reliability of the battery.

[0030] The outer or core parts of the first and second poles are made of the same material as the busbar, which reduces the welding difficulty or the procurement cost of the busbar during the group welding process. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the connection between the first electrode post and the busbar in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the first pole post in an embodiment of the present invention;

[0033] Figure 3 This is a front view of the welding of the first electrode post and the busbar provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the busbar structure in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the connection between the second pole and the busbar in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the structure of the second pole in an embodiment of the present invention;

[0037] Figure 7 This is a front view of the welding of the second pole and the busbar provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the first structure of a battery cell provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the second structure of a battery cell provided in an embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of the third structure of a battery cell provided in an embodiment of the present invention;

[0041] Figure 11 This is a schematic diagram of the battery pack provided in an embodiment of the present invention.

[0042] In the picture:

[0043] 1. Battery casing; 11. Cover plate; 12. Casing body; 2. Busbar; 21. Mounting groove; 22. Receiving groove; 3. Terminal post; 31. Outer layer; 311. Welding boss; 312. Sealing weld; 32. Core; 301. First terminal post; 302. Second terminal post; 4. Busbar. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] like Figures 1 to 7As shown, this embodiment provides a battery cell, which includes a battery casing 1, a battery cell, a busbar 2, and a terminal post 3. The battery casing 1 includes a cover plate 11 and a casing body 12. The casing body 12 has an opening, and the cover plate 11 is disposed at the opening. The battery cell is disposed inside the battery casing 1 and includes a core portion 32 and a tab. The core portion 32 is connected to the tab. The busbar 2 is disposed inside the battery casing 1 and is located between the battery cell and the cover plate 11. The busbar 2 is connected to the tab. The terminal post 3 includes an outer layer portion 31 and a core portion 32. The outer layer portion 31 covers the outer periphery of the core portion 32. One end of the core portion 32 facing the busbar 2 protrudes from the outer layer portion 31. The terminal post 3 passes through the battery casing 1 and is welded to the busbar 2. The outer layer portion 31 is sealed and welded to the busbar 2 and sealed and connected to the cover plate 11. The material of the outer layer portion 31 is different from the material of the core portion 32.

[0049] The terminal post 3 passes through the battery casing 1 and is welded to the busbar 2 to achieve the connection between the terminal post 3 and the busbar 2. Since the outer layer 31 covers the outer periphery of the core 32, the outer layer 31 and the busbar 2 are sealed by welding, and the welding between the outer layer 31 and the busbar 2 forms a sealing weld 312. This sealing weld 312 permanently and physically isolates the electrolyte inside the battery cell from the bonding surface between the core 32 and the outer layer 31 inside the terminal post 3, as well as the core 32 with a higher potential. This eliminates the conditions for the coexistence of electrolyte and dissimilar metals, thereby fundamentally preventing the risk of electrochemical corrosion inside the terminal post 3 and greatly improving the long-term safety and reliability of the battery.

[0050] In some embodiments, one of the outer layer 31 and the core 32 is made of copper or a copper-aluminum alloy, and the other is made of aluminum or an aluminum alloy.

[0051] For example, the core 32 uses copper or a copper alloy with excellent conductivity to ensure low internal resistance and high current carrying capacity; the outer layer 31 uses aluminum or an aluminum alloy, which is low-cost and has good weldability. With this structure, the battery pack can be assembled entirely using aluminum busbars 4 and aluminum-aluminum laser welding, making the process uniform and simple.

[0052] For example, the core 32 is made of lightweight, low-cost aluminum or aluminum alloy; the outer layer 31 is made of highly conductive copper or copper alloy. In this structure, copper acts as the negative electrode and is corrosion-resistant, allowing the core 32 to be connected to the busbar 2, resulting in low cost and a simple, standardized manufacturing process.

[0053] In some embodiments, the outer layer 31 has a welding boss 311 extending radially, the busbar 2 has a mounting groove 21, and the welding boss 311 is welded to the mounting groove 21 by laser welding.

[0054] The welding boss 311 facilitates the welding connection between the outer layer 31 and the busbar 2. The welding boss 311 can fill the mounting groove 21, thereby preventing the electrolyte from entering the mounting groove 21 and being unable to flow out, thus preventing the electrolyte from accumulating in the mounting groove 21.

[0055] like Figure 4 As shown, a receiving groove 22 is further provided at the bottom of the mounting groove 21.

[0056] Since the core 32 protrudes from the end facing the busbar 2 and is disposed with the outer layer 31, in order to enable the core 32 to be bonded to the busbar 2, the receiving groove 22 is provided to accommodate the protruding part of the core 32, avoid the gap between the outer layer 31 and the busbar 2, and thus ensure the bonding and welding of the pole post 3 and the busbar 2.

[0057] In some embodiments, the length of the protrusion of the core 32 toward the end of the busbar 2 is h, where h is 2-10 mm.

[0058] For example, the value of h can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, and there is no specific limitation on the value of h.

[0059] When h is 2mm, it ensures that the core 32 protrudes from the busbar 2, so that the core 32 can be welded to the busbar 2. When h is 10mm, it ensures that the core 32 has enough length to be welded to the busbar 2, thus firmly welding the core 32 to the busbar 2.

[0060] In some embodiments, the diameter of the welding boss 311 is the same as the diameter of the mounting groove 21, and the height of the welding boss 311 is less than or equal to the depth of the mounting groove 21.

[0061] The diameter of the welding boss 311 is the same as the diameter of the mounting groove 21, so that the welding boss 311 can fill the mounting groove 21 completely. The height of the welding boss 311 is less than or equal to the depth of the mounting groove 21, which can provide a space for the formed sealing weld 312. The sealing weld 312 can connect the welding boss 311 to the groove wall of the mounting groove 21 and the side of the busbar 2 away from the battery cell, thereby filling the mounting groove 21 completely. The groove wall of the mounting groove 21 is sealed to the welding boss 311, thus preventing the electrolyte from entering the mounting groove 21 and reacting with the core 32 and outer layer 31 of the electrode post 3, which would cause the electrode post 3 to be corroded.

[0062] like Figure 3 , Figures 7 to 10As shown, in some embodiments, the pole 3 includes a first pole 301 and a second pole 302. Both the first pole 301 and the second pole 302 include an outer layer 31 and a core 32. The end of the core 32 of the first pole 301 facing away from the busbar 2 does not protrude from the outer layer 31. The end of the outer layer 31 of the first pole 301 facing away from the busbar 2 is provided with a groove. The groove facilitates the welding of the first pole 301 to the busbar 4. The end of the core 32 of the second pole 302 facing away from the busbar 2 protrudes from the outer layer 31. The protrusion of the core 32 of the second pole 302 facilitates the welding of the second pole 302 to the busbar 4, thereby achieving the purpose of connecting the first pole 301 and the second pole 302 to the busbar 4.

[0063] In the first terminal 301 and the second terminal 302, one is a positive terminal and the other is a negative terminal.

[0064] In some embodiments, the outer layer 31 and the cover plate 11 are covered by injection molding, or the outer layer 31 and the cover plate 11 are sealed by welding, or a sealing ring is provided between the outer layer 31 and the cover plate 11.

[0065] For example, when the outer layer 31 and the cover plate 11 are encapsulated by injection molding, that is, when the electrode post 3 is installed through the through hole of the cover plate 11, the plastic material fills the gap between the electrode post 3 and the cover plate 11 to form an encapsulation structure. The plastic also serves to seal, prevent detachment, and resist tension and rotation, preventing the electrode post 3 from loosening or the electrolyte from leaking due to high temperature or vibration, and the plastic also serves as insulation.

[0066] For example, the outer layer 31 is sealed and welded to the cover plate 11, that is, the electrode post 3 is installed through the through hole of the cover plate 11, and then the outer peripheral surface of the outer layer 31 is sealed and welded to the cover plate 11. Under the action of welding, a filling weld is formed between the outer layer 31 and the cover plate 11, thereby filling the gap between the electrode post 3 and the cover plate 11. The filling weld also plays the roles of sealing, preventing detachment and resisting tension and rotation, preventing the electrode post 3 from loosening or the electrolyte from leaking due to high temperature or vibration.

[0067] For example, a sealing ring is provided between the outer layer 31 and the cover plate 11, that is, the sealing ring fills the outer layer 31 and the cover plate 11. The sealing ring is a rubber ring, so that the sealing ring can achieve the function of an insulating sealing ring.

[0068] In some embodiments, the middle portion of the busbar 2 is welded to the outer layer 31 and the core portion 32 by laser penetration welding.

[0069] It should be noted that laser welding technology is a fusion welding technology that uses a high-energy-density laser beam as a heat source. It achieves connection by melting materials through a focused laser beam. Its principle is based on the generation of in-phase light waves by stimulated radiation of the medium to form a high-energy laser beam.

[0070] Laser welding minimizes the amount of heat required, resulting in a small range of metallographic changes in the heat-affected zone and minimal deformation due to heat conduction. It eliminates the need for electrodes, thus avoiding concerns about electrode contamination or damage. Furthermore, as it is a non-contact welding process, equipment wear and deformation are minimized. The laser beam is easily focused, aligned, and guided by optical instruments, allowing it to be placed at an appropriate distance from the workpiece and further guided among surrounding equipment or obstacles—a limitation imposed by other welding methods. Secondly, the workpiece can be placed in a closed space (vacuum-sealed or under controlled internal gas environment). The laser beam can be focused into a very small area, enabling the welding of small, closely spaced components, a wide range of weldable materials, and the joining of various dissimilar materials. Additionally, it is easily automated for high-speed welding and can be digitally or computer-controlled. When welding thin materials or fine-diameter wires, it avoids the remelting issues common in arc welding.

[0071] In some embodiments, the battery cell is a wound or laminated battery cell.

[0072] The battery cell provided by the above solution can eliminate the risk of corrosion. Specifically, the terminal post 3 and the shunt plate achieve an airtight seal through laser sealing welding, which physically isolates the factors that lead to electrochemical corrosion (contact between the electrolyte and dissimilar metals), providing a guarantee for battery reliability. Furthermore, through the composite design of the "core 32-outer layer 31," different functional requirements such as conductivity, weldability, corrosion resistance, and cost are allocated to the most suitable materials, achieving optimal comprehensive performance that cannot be achieved with a single material. The uniform external interface material of the battery cell terminal post 3 allows the battery pack to use a single material for the busbar 4 and implement laser welding technology, resulting in high production efficiency, good quality consistency, and low cost.

[0073] The present invention also provides a method for manufacturing a battery cell, for manufacturing a battery cell according to any of the above-mentioned schemes, comprising the following steps:

[0074] S101. Manufacturing the pole post 3 and making one end of the core 32 protrude from the mounting plane of the outer layer 31;

[0075] The pole post 3 is obtained by using a copper-aluminum composite rod. The copper-aluminum composite rod is machined by a CNC lathe or machining center to form a composite pole post 3. The core 32 of each pole post 3 protrudes from the mounting plane of the outer layer 31.

[0076] S102. Using high-energy beam welding technology, the welding boss 311 is welded to the mounting groove 21 by laser welding, and the bottom of the outer layer 31 and the core 32 are welded to the busbar 2 through the weld.

[0077] The high-energy beam welding process firmly welds the portion of the core 32 protruding from the outer layer 31 to the busbar 2 to form a weld with excellent airtightness, ensuring electrolyte isolation. Additionally, the outer layer 31, the bottom of the core 32, and the busbar 2 are welded together to enhance the connection between the busbar 2 and the first electrode 301 or the second electrode 302.

[0078] S103. Connect the battery cell's tabs to the busbar 2;

[0079] For example, the tabs of the battery cell are connected to the busbar 2 by ultrasonic welding, laser welding, or other methods.

[0080] S104. Install the battery cell into the battery casing 1, and seal the terminal post 3 through the cover plate 11 and connect the cover plate 11 to the casing.

[0081] S105. After drying, the battery is injected with electrolyte and formed, and then packaged.

[0082] During the battery pack assembly stage, the busbar 4 of the same material is precisely welded to the exposed vertical or end face of the pole post 3 using laser sealing welding technology.

[0083] The battery pack is obtained through the above method. Since the outer layer 31 covers the outer periphery of the core 32, the terminal post 3 passes through the battery casing 1 and is welded to the busbar 2 to achieve the connection between the terminal post 3 and the busbar 2. The outer layer 31 and the busbar 2 are sealed by welding, and the welding between the outer layer 31 and the busbar 2 forms a sealing weld 312. This sealing weld 312 permanently and physically isolates the electrolyte inside the battery cell from the bonding surface between the core 32 and the outer layer 31 inside the terminal post 3, as well as the core 32 with a higher potential. This eliminates the conditions for the coexistence of electrolyte and dissimilar metals, thereby fundamentally preventing the risk of electrochemical corrosion inside the terminal post 3 and greatly improving the long-term safety and reliability of the battery. In addition, the outer layer 31 or core 32 of the first terminal post 301 and the second terminal post 302 are made of the same material as the busbar 4. That is, the outer layer 31 or core 32 and the busbar 4 are made of the same material, which reduces the welding difficulty or the procurement cost of the busbar 4 during the group welding process.

[0084] In some embodiments, the laser power in the high-energy beam welding process is 2-8KW, the welding speed is 20-100mm / s, and the shielding gas is nitrogen or helium.

[0085] For example, the laser power can be selected as 2KW, 3KW, 4KW, 5KW, 6KW, 7KW or 8KW, the welding speed can be selected as 20mm / s, 30mm / s, 40mm / s, 50mm / s, 60mm / s, 70mm / s, 80mm / s, 90mm / s or 100mm / s, and the shielding gas is nitrogen or helium.

[0086] For example, the outer layer 31 is made of aluminum or aluminum alloy, and the core 32 is made of copper or copper alloy. The bottom of the outer layer 31 is designed with a welding boss 311 during processing. The welding boss 311 is connected to the mounting groove 21 of the busbar 2 by laser sealing welding, forming a sealed weld 312. Simultaneously, the bottom of the busbar 2 undergoes two laser penetration welds to reconnect the core 32 and the outer surface of the electrode post 3 to the busbar 2, enhancing its conductivity. The processing methods for the first electrode post 301 and the second electrode post 302 are the same. The airtightness of the sealed weld 312 is extremely important, ensuring its long-term effective barrier against electrolyte penetration, preventing it from penetrating and contacting the heterogeneous core 32 inside the electrode post 3 and the copper-aluminum interface. This perfectly avoids electrochemical corrosion caused by the formation of a galvanic cell between aluminum and copper in the electrolyte. The electrode posts 3 are then welded to the tabs of the corresponding battery cells. The welded battery cells are installed into the battery casing 1, and the terminals 3 are passed through the cover plate 11. The casing body 12 and the cover plate 11, the terminals 3 and the casing, and the terminals 3 and the cover plate 11 are sealed and welded together. The battery cells are then vacuum dried. Electrolyte is injected into the vacuum-dried battery cells, and the cells are then subjected to static soaking, formation, aging, and capacity testing in sequence to obtain a power battery cell based on the functionally partitioned terminals 3.

[0087] like Figure 11 As shown, the present invention also provides a battery pack comprising the battery cells provided by any of the above-described solutions.

[0088] Since the battery pack includes individual battery cells, and the outer layer 31 covers the outer periphery of the core 32, the core 32 passes through the battery casing 1 and is welded to the busbar 2 to connect the terminal post 3 and the busbar 2. The outer layer 31 and the busbar 2 are sealed by welding, and the welding between the outer layer 31 and the busbar 2 forms a sealing weld 312. This sealing weld 312 permanently and physically isolates the electrolyte inside the battery cell from the bonding surface between the core 32 and the outer layer 31 inside the terminal post 3, as well as the core 32 with a higher potential. This eliminates the conditions for the coexistence of electrolyte and dissimilar metals, thereby fundamentally preventing the risk of electrochemical corrosion inside the terminal post 3 and greatly improving the long-term safety and reliability of the battery.

[0089] This battery pack consists of multiple individual battery cells connected in series and parallel via busbar 4. All connection points are laser-sealed welded, ensuring a consistent process and high reliability. For example, the welding area of ​​busbar 4 corresponding to terminal post 3 is made entirely of aluminum.

[0090] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery cell, characterized in that, include: A battery casing (1) includes a cover plate (11) and a casing body (12), the casing body (12) having an opening, and the cover plate (11) being disposed at the opening; The battery cell is disposed inside the battery casing (1), and the battery cell includes a core body and a tab, wherein the core body is connected to the tab; A busbar (2) is disposed inside the battery casing (1), the busbar (2) is located between the battery cell and the cover plate (11), and the busbar (2) is connected to the electrode tab; The electrode post (3) includes an outer layer (31) and a core (32). The outer layer (31) covers the outer periphery of the core (32). The end of the core (32) facing the busbar (2) protrudes from the outer layer (31). The electrode post (3) passes through the battery casing (1) and is welded to the busbar (2). Both the outer layer (31) and the core (32) are welded to the busbar (2). The outer layer (31) is sealed to the cover plate (11). The material of the outer layer (31) is different from that of the core (32). The outer layer (31) is welded to the busbar (2) to form a sealing weld. The sealing weld permanently and physically isolates the electrolyte inside the battery cell from the bonding surface between the core (32) inside the terminal post and the outer layer (31), as well as the core (32) with a higher potential. The terminal post (3) includes a first terminal post (301) and a second terminal post (302). The outer layer (31) of the first terminal post (301) has a groove at one end away from the busbar (2), and the core (32) of the second terminal post (302) protrudes from the outer layer (31) at one end away from the busbar (2).

2. The battery cell according to claim 1, characterized in that, Of the outer layer (31) and the core (32), one is made of copper or copper-aluminum alloy, and the other is made of aluminum or aluminum alloy.

3. The battery cell according to claim 1, characterized in that, The outer layer (31) has a welding boss (311) extending radially, the busbar (2) has a mounting groove (21), and the welding boss (311) is laser welded into the mounting groove (21); and / or, The middle part of the busbar (2) is welded to the outer layer (31) and the core (32) by laser penetration welding.

4. The battery cell according to any one of claims 1-3, characterized in that, The outer layer (31) and the cover plate (11) are covered by injection molding, or the outer layer (31) and the cover plate (11) are sealed by welding, or a sealing ring is provided between the outer layer (31) and the cover plate (11).

5. The battery cell according to any one of claims 1-3, characterized in that, The length of the protrusion of the core (32) toward the end of the busbar (2) is h, where h is 2-10mm.

6. A method for manufacturing a single battery cell, characterized in that, The method for manufacturing a battery cell according to any one of claims 1-5 includes the following steps: S101. Manufacturing a pole post (3) and making one end of the core (32) protrude from the mounting plane of the outer layer (31); S102. Using high-energy beam welding process, the welding boss (311) is welded to the mounting groove (21) of the busbar (2) by laser welding, and the bottom of the outer layer (31) and the core (32) are welded to the busbar (2) through penetration. S103. Connect the battery cell's tabs to the busbar (2); S104. Install the battery cell into the battery casing (1), and seal the terminal post (3) through the cover plate (11) and connect the cover plate (11) to the casing; S105. After drying, the battery is injected with electrolyte and formed, and then packaged.

7. The method for manufacturing a single battery cell according to claim 6, characterized in that, In high-energy beam welding, the laser power is 2-8KW, the welding speed is 20-100mm / s, and the shielding gas is nitrogen or helium.

8. A battery pack, characterized in that, It includes a busbar (4) and two or more battery cells as described in any one of claims 1-5, the battery cells being connected in series and parallel via the busbar (4).

9. The battery pack according to claim 8, characterized in that, The material of the outer layer (31) is the same as that of the busbar (4).

Images