Battery module, lithium ion battery and preparation process thereof

Abstract

The application provides a battery module, a lithium ion battery and a preparation process thereof. The lithium ion battery comprises a shell and a roll core. The shell comprises a shell body and a cover cap. The cover cap is arranged on the shell body. The roll core is arranged in the shell body and is electrically connected with the cover cap and the shell body respectively. The shell body is used for containing electrolyte for infiltrating the roll core. The material of the shell body is iron alloy. The thermal conductivity coefficient of the iron alloy is 36 W / (m.C) to 60 W / (m.C). The main component of the positive active material of the pole piece of the roll core is lithium manganate. The lithium ion battery has high thermal stability of the positive active material. The safety hazard of the battery caused by the decomposition of the positive active material to produce gas under high temperature is avoided. Meanwhile, the heat dissipation performance of the shell body made of the iron alloy material can be better adapted. The safety performance of the lithium ion battery is improved. The internal contact impedance between active substances of the lithium ion battery is small. The problem that the lithium ion battery is prone to failure is avoided. The electric conductivity reliability of the lithium ion battery is improved.

Description

Technical Field

[0001] This invention relates to the technical field of lithium-ion batteries, and in particular to a battery module, a lithium-ion battery, and their manufacturing process. Background Technology

[0002] Large cylindrical lithium-ion batteries (referred to as large cylindrical batteries), especially large cylindrical rechargeable batteries, are characterized by high and stable output voltage and are widely used in power tools, backup power, lawn lights, solar lights, rechargeable two-wheeled vehicles, and toy models. However, with the continuous development of large cylindrical batteries, especially the upgrading of battery energy storage requirements, traditional large cylindrical batteries still suffer from problems related to heat dissipation, safety, energy density, and high cost. A good solution that can comprehensively address these issues is lacking. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a battery module, lithium-ion battery and its manufacturing process that have better overall performance in terms of heat dissipation, safety, energy density and high cost.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A lithium-ion battery includes a casing and a core. The casing includes a housing and a cap. The cap covers the housing. The core is housed inside the housing and is electrically connected to the cap and the housing. The housing contains an electrolyte that wets the core.

[0006] The shell is made of iron alloy, and the thermal conductivity of the iron alloy is 36W / (m.℃)~60W / (m.℃).

[0007] The main component of the positive electrode active material of the core electrode sheet is lithium manganese oxide;

[0008] The core is provided with a positive electrode tab structure and a negative electrode tab structure at both ends. The positive electrode tab structure is used to electrically connect to the cap through the positive electrode current collector, and the negative electrode tab structure is used to electrically connect to the shell through the negative electrode current collector.

[0009] In one embodiment, the lithium manganese oxide content of the positive electrode active material is 60% to 100%.

[0010] In one embodiment, the housing is a one-piece stamped structure.

[0011] In one embodiment, the housing is a steel shell, the height of the housing is 110 mm to 220 mm, and the diameter of the housing is 30 mm to 60 mm.

[0012] In one embodiment, the lithium-ion battery is model 4680, 34145, 60220, or 30110.

[0013] In one embodiment, the thermal conductivity of the iron alloy is 45 W / (m·℃), and the resistivity of the iron alloy is 10 × 10⁻⁸ Ω·m.

[0014] In one embodiment, the electrical parameters of the lithium-ion battery are specifically as follows:

[0015] The voltage is 2.75V~4.2V, the capacitance is 8 Ah ~80A.h, and the resistance is 0.8mΩ~4mΩ.

[0016] In one embodiment, the positive current collector is an aluminum current collector, and the negative current collector is a nickel current collector; and / or,

[0017] The surface of the housing is coated with a nickel layer.

[0018] In one embodiment, the positive electrode tab is welded to the positive electrode current collector.

[0019] In one embodiment, the lithium-ion battery further includes an insulating covering structure that covers the periphery where the positive electrode tab structure connects to the positive electrode current collector.

[0020] In one embodiment, the positive current collector is formed with an electrical connection structure, which is electrically connected to the cap.

[0021] In one embodiment, the positive current collector includes a current collector body and the electrical connection structure. The current collector body has a stamped groove. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the cap.

[0022] In one embodiment, the positive current collector is formed with the electrical connection structure by a stamping process; and / or,

[0023] The lithium-ion battery also includes an insulating covering structure, which covers the periphery where the positive electrode tab connects to the positive electrode current collector, and the insulating covering structure is arranged around the positive electrode current collector.

[0024] In one embodiment, the negative electrode tab is welded to the negative electrode current collector, and the negative electrode current collector is welded to the housing.

[0025] In one embodiment, the cap includes a seal, a conductive explosion-proof component, and a top cover. The seal is sealed to the peripheral wall of the opening of the housing. The seal covers the periphery of the conductive explosion-proof component. The conductive explosion-proof component is connected to the top cover and is electrically connected to the positive electrode tab. The top cover has an air vent.

[0026] In one embodiment, the conductive explosion-proof assembly includes a conductive explosion-proof component, an insulating pad, and a safety valve. The conductive explosion-proof component is connected to the top cover and is electrically connected to the positive omnidirectional tab. The periphery of the safety valve is connected to the conductive explosion-proof component through the insulating pad. The safety valve abuts against the conductive explosion-proof component and is electrically connected to the positive omnidirectional tab.

[0027] In one embodiment, the lithium-ion battery further includes a positive electrode current collector, which is welded to the positive electrode tab and the safety valve respectively.

[0028] In one embodiment, the positive current collector is formed with an electrical connection structure, which is welded to the safety valve.

[0029] In one embodiment, the positive current collector includes a current collector body and the electrical connection structure. The current collector body has a stamped groove. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the safety valve.

[0030] In one embodiment, the conductive explosion-proof component has an explosion-proof cracking zone formed thereon, the explosion-proof cracking zone being designed to crack under a predetermined pressure.

[0031] In one embodiment, the explosion-proof cracking zone has a circular, triangular, quadrilateral, or polygonal outline; and / or, the explosion-proof cracking zone is a groove structure.

[0032] A process for manufacturing a lithium-ion battery includes providing a casing and a cap; the process further includes:

[0033] A core is formed, wherein the main component of the positive electrode active material of the core electrode sheet is lithium manganese oxide;

[0034] Positive electrode tab structure and negative electrode tab structure are respectively formed at both ends of the winding core;

[0035] The core is placed in the receiving slot of the housing;

[0036] The negative electrode omnipolar structure is connected to the housing via a negative electrode current collector, so that the negative electrode omnipolar structure is used to electrically connect to the housing via the negative electrode current collector.

[0037] Electrolyte is injected into the receiving tank;

[0038] The positive electrode omnipolar structure is connected to the cap via a positive electrode current collector, so that the positive electrode omnipolar structure is electrically connected to the cap via the positive electrode current collector;

[0039] The cap is sealed at the opening of the housing;

[0040] The shell is made of an iron alloy, and the thermal conductivity of the iron alloy is 36 W / (m·℃) to 60 W / (m·℃).

[0041] In one embodiment, the step of forming the core includes:

[0042] A positive electrode sheet and a negative electrode sheet are formed separately, wherein the main component of the positive electrode active material of the positive electrode sheet is lithium manganese oxide, and an aluminum foil empty foil area is formed on at least one side of the positive electrode sheet, and a copper foil empty foil area is formed on at least one side of the negative electrode sheet.

[0043] The positive electrode, the separator, and the negative electrode are sequentially stacked and wound to form a core;

[0044] The specific steps of forming a positive electrode tab structure and a negative electrode tab structure at both ends of the core are as follows: flattening the empty aluminum foil area and the empty copper foil area of ​​the core respectively, so that the empty aluminum foil area forms the positive electrode tab structure and the empty copper foil area forms the negative electrode tab structure.

[0045] In one embodiment, the step of separately forming the positive electrode sheet and the negative electrode sheet specifically includes:

[0046] A first layer structure with the positive electrode active material is formed by coating aluminum foil to form a positive electrode semi-finished product, such that there is an aluminum foil void area between the edge of the aluminum foil and the edge of the first layer structure.

[0047] A second layer structure with a negative electrode active material is formed by coating copper foil to form a negative electrode semi-finished product, such that there is a copper foil void area between the edge of the copper foil and the edge of the second layer structure.

[0048] The positive electrode semi-finished product and the negative electrode semi-finished product are respectively subjected to rolling operations.

[0049] In one embodiment, before the step of placing the winding core into the receiving groove of the housing, and after the step of forming positive electrode tab structures and negative electrode tab structures at both ends of the winding core respectively, the manufacturing process further includes:

[0050] The positive electrode omnipolar structure is welded to the positive electrode current collector, and the negative electrode omnipolar structure is welded to the negative electrode current collector;

[0051] The step of connecting the negative electrode omnipolar structure to the housing via the negative electrode current collector plate specifically involves welding the negative electrode current collector plate to the housing.

[0052] The specific step of connecting the positive electrode omnipolar structure to the cap via the positive electrode current collector is as follows: welding the positive electrode current collector to the cap.

[0053] In one embodiment, before the step of injecting electrolyte into the receiving tank and after the step of connecting the negative electrode tab structure to the housing via the negative electrode current collector, the manufacturing process further includes: stamping the positive electrode current collector to form an electrical connection structure on the positive electrode current collector;

[0054] The step of welding the positive current collector to the cap specifically includes: welding the electrical connection structure to the cap; and / or...

[0055] After the step of welding the negative electrode current collector to the housing, and before the step of injecting electrolyte into the receiving tank, the manufacturing process further includes:

[0056] The housing is grooved to define the position of the winding core.

[0057] A battery module includes a lithium-ion battery, which is prepared according to the lithium-ion battery preparation process described in any of the above embodiments.

[0058] In one embodiment, the battery module further includes a battery mounting bracket, to which the housing is mounted and fixed.

[0059] In one embodiment, the outer peripheral wall of the housing is formed with a crimping groove, and the inner peripheral wall of the housing is formed with a limiting flange at a position corresponding to the crimping groove, so that the winding core is limited to the receiving groove. The battery fixing bracket is formed with an assembly protrusion, which is located in the crimping groove and abuts against the housing.

[0060] Compared with the prior art, the present invention has at least the following advantages:

[0061] 1. The aforementioned lithium-ion battery, due to the fact that the positive electrode active material of the core is mainly lithium manganese oxide, has a good energy density. Furthermore, the presence of full-tab structures at both ends of the core reduces its internal resistance. One full-tab structure is electrically connected to the cap via the positive current collector, while the other is electrically connected to the casing via the negative current collector. This allows for rapid conduction of electricity within the lithium-ion battery, avoiding excessive internal heat generation and preventing the formation of hydrofluoric acid within the casing. The positive electrode active material exhibits high thermal stability, preventing decomposition and gas generation at high temperatures that could lead to battery safety hazards. It also better adapts to the heat dissipation performance of the iron alloy casing, improving the safety performance of the lithium-ion battery. This ensures low contact resistance between the internal active materials, preventing battery failure and enhancing conductivity reliability.

[0062] 2. Due to the thermal conductivity of iron alloys being 36W / (m.℃)~60W / (m.℃), the casing has good heat dissipation performance. Furthermore, since the casing material is iron alloy, the casing has good structural strength, thereby improving the structural safety of lithium-ion batteries. Thus, while improving the energy density, heat dissipation, and safety of lithium-ion batteries, especially for large-capacity lithium-ion batteries, the manufacturing cost of lithium-ion batteries is effectively reduced. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a schematic diagram of the structure of a lithium-ion battery according to one embodiment;

[0065] Figure 2 for Figure 1 The diagram shows a cross-sectional view of a lithium-ion battery.

[0066] Figure 3 for Figure 2 A partially enlarged schematic diagram of the lithium-ion battery shown.

[0067] Figure 4 A flowchart illustrating the fabrication process of a lithium-ion battery according to one embodiment;

[0068] Figure 5 This is a schematic diagram of the cap structure of a lithium-ion battery according to another embodiment. Detailed Implementation

[0069] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0070] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0072] This application provides a lithium-ion battery, including a casing and a core. The casing includes a housing and a cap, the cap being disposed on the housing. The core is housed within the housing and electrically connected to both the cap and the housing. The housing contains an electrolyte that wets the core. The housing is made of an iron alloy with a thermal conductivity of 36 W / (m·℃) to 60 W / (m·℃). The positive electrode active material of the core's electrode sheet is primarily composed of lithium manganese oxide. A positive electrode tab structure and a negative electrode tab structure are respectively provided at both ends of the core. The positive electrode tab structure is electrically connected to the cap via a positive current collector, and the negative electrode tab structure is electrically connected to the housing via a negative current collector.

[0073] The aforementioned lithium-ion battery, due to the fact that the positive electrode active material of the core is mainly lithium manganese oxide, possesses good energy density. Furthermore, the presence of full-tab structures at both ends of the core reduces its internal resistance. One full-tab structure is electrically connected to the cap via a positive current collector, while the other is electrically connected to the casing via a negative current collector. This allows for rapid heat dissipation during internal conduction, avoiding excessive internal heat generation and preventing the formation of hydrofluoric acid within the casing. It also better adapts to the heat dissipation performance of the iron alloy casing, thus improving the overall performance of the lithium-ion battery. The safety performance of the sub-cell ensures low contact resistance between the internal active materials of the lithium-ion battery, avoiding the problem of easy failure of lithium-ion batteries and improving the conductivity reliability of lithium-ion batteries. Since the thermal conductivity of iron alloy is 36W / (m.℃)~60W / (m.℃), the casing has good heat dissipation performance. Furthermore, since the casing material is iron alloy, the casing has good structural strength, thus making the structural safety of lithium-ion batteries high. In this way, while improving the energy density, heat dissipation and safety of lithium-ion batteries, especially for large-capacity lithium-ion batteries, the manufacturing cost of lithium-ion batteries is effectively reduced.

[0074] To better understand the technical solution and beneficial effects of this application, the following detailed description is provided in conjunction with specific embodiments:

[0075] like Figure 1 and Figure 2 As shown, a lithium-ion battery 10 of one embodiment includes a casing 100 and a core 200. The casing 100 includes a housing 110 and a cap 120. The cap 120 covers the housing 110. The core 200 is housed within the housing 110 and is electrically connected to both the cap 120 and the housing 110. The housing 110 contains an electrolyte that wets the core 200. In one embodiment, the housing 110 is made of an iron alloy with a thermal conductivity of 36 W / (m·℃) to 60 W / (m·℃). The main component of the positive electrode active material of the core 200's electrode sheet is lithium manganese oxide, meaning that the majority of the positive electrode active material of the core 200's electrode sheet is lithium manganese oxide. The core 200 is provided with a positive full-pole tab structure and a negative full-pole tab structure at both ends. The positive full-pole tab structure is used to electrically connect to the cap 120 through the positive current collector 300, and the negative full-pole tab structure is used to electrically connect to the housing 110 through the negative current collector 400, so that the two ends of the core 200 are electrically connected to the cap 120 and the housing 110 respectively.

[0076] Traditional high-capacity lithium-ion batteries suffer from high heat generation. To address this issue, traditional lithium-ion batteries use aluminum casings and multiple tabs for matching. While this reduces heat generation, it increases the processing steps for the casing, thus increasing the manufacturing difficulty. Furthermore, to better meet the energy density requirements of large cylindrical batteries and avoid excessive HF generation, the positive electrode active material of the lithium-ion battery core primarily uses ternary materials, resulting in higher costs and lower safety. Therefore, traditional large cylindrical batteries still suffer from problems related to heat dissipation, safety, energy density, and high cost, and a good solution that comprehensively addresses these issues is lacking.

[0077] The lithium-ion battery 10 of this application has a good energy density because the positive electrode active material of the core 200 is mainly composed of lithium manganese oxide. Furthermore, because the core 200 has full-tab structures at both ends, one full-tab structure is electrically connected to the cap 120 through the positive current collector 300, and the other full-tab structure is directly electrically connected to the casing 110 through the negative current collector 400. This allows for rapid conduction of electricity within the lithium-ion battery 10, reducing resistance loss and heat generation, thus avoiding excessive internal heat generation. It also prevents the formation of hydrofluoric acid within the casing 110 due to the high thermal stability of the positive electrode active material, preventing decomposition and gas generation at high temperatures. This design eliminates safety hazards and better adapts to the heat dissipation performance of the iron alloy casing 110, improving the safety performance of the lithium-ion battery 10. It ensures low contact resistance between the internal active materials of the lithium-ion battery 10, avoiding the problem of easy failure of lithium-ion batteries and improving the conductivity reliability of the lithium-ion battery 10. Since the thermal conductivity of iron alloy is 36W / (m.℃)~60W / (m.℃), the casing 110 has good heat dissipation performance. Furthermore, because the casing 110 is made of iron alloy, it has good structural strength, thus making the structural safety of the lithium-ion battery 10 higher. Therefore, while improving the energy density, heat dissipation, and safety of the lithium-ion battery 10, especially for large-capacity lithium-ion batteries 10, the manufacturing cost of the lithium-ion battery 10 is effectively reduced.

[0078] It should be noted that the thermal conductivity of iron alloys ranges from 36 W / (m·℃) to 60 W / (m·℃), making it a relatively moderate value. On the one hand, if the thermal conductivity of the iron alloy is too low (e.g., less than 36 W / (m·℃), the battery casing will have poor heat dissipation performance under high-temperature conditions. When lithium-ion batteries are charged and discharged at room temperature or high ambient temperatures (e.g., 40℃ or even higher), the heat generated inside the battery cannot be dissipated in time, causing the internal temperature of the battery to rise too high. Consequently, the positive electrode active material, especially lithium manganese oxide positive electrode active material, will decompose and produce gas at high temperatures. The dissolution of manganese can lead to safety hazards and significant deterioration of the battery's electrochemical performance. On the other hand, when used in low-temperature environments (e.g., -10°C or even lower), the heat generated during charging and discharging can cause the internal temperature of the battery to rise appropriately, thereby reducing the polarization of the battery during charging and discharging. If the thermal conductivity of the iron alloy is too high (e.g., greater than 60 W / (m.°C), the heat generated during the low-temperature charging and discharging process of the lithium-ion battery will be rapidly exchanged with the outside environment due to the rapid heat transfer and dissipation of the outer shell, keeping the internal temperature of the battery at a low level, which is detrimental to the low-temperature charging and discharging performance of the battery.

[0079] In one embodiment, the lithium manganese oxide content of the positive electrode active material is 60% to 100%. Further, the lithium manganese oxide content of the positive electrode active material is 70% to 90%, resulting in a higher proportion of lithium manganese oxide in the positive electrode active material. This also allows the thermal conductivity of the lithium manganese oxide to better meet the heat generation limit requirements of the lithium-ion battery 10, thereby giving the lithium-ion battery 10 a better energy density. In this embodiment, the lithium manganese oxide content of the positive electrode active material is 80%, resulting in a higher proportion of lithium manganese oxide in the positive electrode active material. Furthermore, the proportion of lithium manganese oxide in the positive electrode active material is moderate, and this also allows the thermal conductivity of the lithium manganese oxide to better meet the heat generation limit requirements of the lithium-ion battery 10, thereby giving the lithium-ion battery 10 a better energy density.

[0080] In one embodiment, the housing 110 is a one-piece stamped structure, making it easy to process and manufacture. In this embodiment, the housing 110 is made of iron alloy, and the thermal conductivity of iron alloy is 36W / (m.℃)~60W / (m.℃), making the housing 110 easy to form in one piece. Compared with the traditional aluminum shell manufacturing which requires stamping and welding processes, the processing steps of the housing 110 of the lithium-ion battery 10 of this application are simpler, resulting in higher processing efficiency of the lithium-ion battery 10, while also giving the housing 110 better structural strength.

[0081] In one embodiment, the casing 110 is made of steel, with a height of 110 mm to 220 mm and a diameter of 30 mm to 60 mm. This allows for a larger volume of the lithium-ion battery 10, facilitating an increase in the thickness of the casing 110. The casing 110, obtained through a stamping process, exhibits improved structural strength and thermal conductivity. In this embodiment, the lithium-ion battery 10 is a large cylindrical battery, i.e., a high-capacity lithium-ion battery, which better meets the energy storage requirements of the battery module and thus better adapts to the power needs of the power battery. Furthermore, the casing 110 can be made of stainless steel or nickel-plated steel, etc.

[0082] In one embodiment, the lithium-ion battery 10 is designated as 4680, 34145, 60220, or 30110, making it a high-capacity lithium-ion battery. In this embodiment, the lithium-ion battery 10 is a large cylindrical battery.

[0083] In one embodiment, the thermal conductivity of the iron alloy is 40 W / (m·℃) to 50 W / (m·℃), resulting in a good thermal conductivity rate. In another embodiment, the thermal conductivity of the iron alloy is 45 W / (m·℃), and the resistivity of the iron alloy is 10 x 10⁻⁸, resulting in a good balance between thermal conductivity rate and cost. This leads to a better overall balance between heat dissipation performance and cost for the lithium-ion battery 10, thus enabling the lithium-ion battery 10 to have good heat dissipation performance and low cost.

[0084] In one embodiment, the electrical parameters of the lithium-ion battery 10 are as follows: voltage of 2.75V~4.2V, capacity of 8 Ah~80A.h, and resistance of 0.8mΩ~4mΩ, giving the lithium-ion battery 10 good electrical performance.

[0085] In one embodiment, the lithium-ion battery 10 has a current of 950mA to 28000mA.

[0086] To better demonstrate the advantages of the lithium-ion battery of this application, the lithium-ion battery of this application (Example 1) and four conventional lithium-ion batteries (Comparative Example 2, Comparative Example 3, Comparative Example 4 and Comparative Example 5) were tested in terms of safety and energy density. In Comparative Example 1, the lithium-ion battery has a steel casing, both ends of the winding core have full tabs, and the main component of the positive electrode active material of the winding core is lithium manganese oxide. In Comparative Example 2, the lithium-ion battery has a steel casing, both ends of the winding core have full tabs, and the main component of the positive electrode active material of the winding core is lithium iron phosphate. In Comparative Example 3, the lithium-ion battery has an aluminum casing, both ends of the winding core have full tabs, and the main component of the positive electrode active material of the winding core is lithium manganese oxide. In Comparative Example 4, the lithium-ion battery has a steel casing, both ends of the winding core have non-full tabs, and the main component of the positive electrode active material of the winding core is lithium manganese oxide. In Comparative Example 5, the lithium-ion battery has a steel casing, both ends of the winding core have non-full tabs, and the main component of the positive electrode active material of the winding core is ternary material. The data for Example 1 corresponds to three sets, where each set of data is the average of multiple sets of data. The heating power data for Example 1 was adjusted, and the data for Comparative Examples 2-5 are the average of multiple sets of data. The following experimental data were obtained:

[0087]

[0088] As can be seen from the table above, under the same heating power conditions, the safety data of the lithium-ion battery of this application, namely the thermal runaway test data time and temperature, are slightly inferior to those of Comparative Example 2 of lithium iron phosphate, but are superior to those of Comparative Example 3, Comparative Example 4 and Comparative Example 5. Under the premise of a larger maximum current, the lithium-ion battery of this application generates less heat and has better mass energy density, indicating that the lithium-ion battery of this application has better comprehensive performance in terms of energy density, heat dissipation and safety.

[0089] In one embodiment, the positive current collector 300 is made of aluminum, and the negative current collector 400 is made of nickel, giving both the positive and negative current collectors good thermal conductivity. Furthermore, the casing 110 is made of iron alloy, which has a thermal conductivity of 36 W / (m·℃) to 60 W / (m·℃), allowing for rapid heat dissipation from the interior of the lithium-ion battery 10. Because the positive electrode tab structure of the core 200 is connected to the cap 120 via the positive current collector 300, and the negative electrode tab structure is connected to the casing 110 via the negative current collector 400, and due to the difference in materials between the current collectors contacted by the positive and negative current collectors, the negative current collector 400 is directly connected to the casing 110. Compared to the bi-tab method, this results in better heat dissipation performance for the lithium-ion battery 10. And / or, in one embodiment, the surface of the housing is formed with a nickel plating layer to give the housing better heat dissipation performance.

[0090] To ensure a reliable electrical connection between the positive electrode tab and the positive current collector 300, in one embodiment, the positive electrode tab is soldered to the positive current collector 300, thus fixing the positive electrode tab to the positive current collector 300 and ensuring a reliable electrical connection between the positive electrode tab and the positive current collector 300. Further, the positive electrode tab has a first flattened structure, which is soldered to the positive current collector 300, thus soldering the positive electrode tab to the positive current collector 300.

[0091] See also Figure 3 In one embodiment, the lithium-ion battery 10 further includes an insulating covering structure 500. The insulating covering structure 500 covers the periphery where the positive electrode tab structure and the positive electrode current collector 300 are connected, ensuring a reliable insulating connection between the positive electrode tab structure and the positive electrode current collector 300, and preventing short circuits caused by direct contact between the positive electrode tab structure and the positive electrode current collector 300. Further, the insulating covering structure 500 includes an adhesive layer 510 and an insulating sheet 520. The adhesive layer 510 is bonded to the end of the positive electrode tab structure, and the positive electrode current collector 300 is fixed to the end face of the positive electrode tab structure through the adhesive layer 510. The insulating sheet 520 is sleeved at the connection between the positive electrode tab structure and the positive electrode current collector 300, and the insulating sheet 520 is fixed to the adhesive layer 510, so that the insulating covering structure 500 covers the periphery where the positive electrode tab structure and the positive electrode current collector 300 are connected. In this embodiment, the adhesive layer 510 is coated and formed on the end face and outer peripheral wall of the positive electrode tab structure. Furthermore, the insulating sheet 520 has an exposed area 522, exposing a portion of the positive electrode current collector 300 in the exposed area, so that the positive electrode current collector 300 can be externally connected to conduction. Furthermore, the adhesive layer 510 is partially exposed outside the insulating sheet 520, and the adhesive layer 510 is also adhered to the inner wall of the housing 110, so that the core 200 is reliably installed and positioned within the housing 110.

[0092] See also Figure 3 In one embodiment, the positive current collector 300 has an electrical connection structure that is electrically connected to the cap, allowing the positive current collector 300 to be externally led out for conduction. This electrical connection between the positive current collector and the cap reduces internal losses in the lithium-ion battery 10 and makes the structure of the lithium-ion battery 10 more compact. In this embodiment, the tab structure is led out through an exposed area. In one embodiment, the positive current collector 300 includes a current collector body 310 and an electrical connection structure 320. The current collector body 310 has a stamped groove 312. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the cap, ensuring reliable electrical connection between the electrical connection structure and both the current collector body and the cap. This also reduces the difficulty of processing the tab structure formed by the positive current collector 300, thus making the structure of the lithium-ion battery 10 more compact.

[0093] In one embodiment, the positive electrode current collector 300 is formed with an electrical connection structure through a stamping process, which reduces the processing difficulty of the electrical connection structure. It is understood that in other embodiments, the positive electrode current collector 300 is not limited to being formed with an electrical connection structure through a stamping process. For example, the positive electrode current collector 300 is formed with an electrical connection structure through a welding process. And / or, in one embodiment, the lithium-ion battery 10 further includes an insulating covering structure 500, which covers the periphery of the connection between the positive electrode tab and the positive electrode current collector 300. The insulating covering structure 500 surrounds the electrical connection structure, ensuring a reliable insulating connection between the positive electrode tab structure and the positive electrode current collector 300, preventing direct contact and short circuits caused by the positive electrode tab structure and the positive electrode current collector 300, and also preventing short circuits caused by contact between the electrical connection structure and the inner wall of the housing 110, thereby ensuring reliable lead-out of the electrical connection structure. In this embodiment, the insulating covering structure 500 has an exposed area, through which the tab structure is led out.

[0094] In one embodiment, the negative electrode lug is welded to the negative electrode current collector 400, and the negative electrode current collector 400 is welded to the steel shell, so that the negative electrode current collector 400 is reliably fixedly connected to the negative electrode lug and the steel shell respectively, thereby reliably electrically connecting the negative electrode lug to the negative electrode current collector 400. In this embodiment, the negative electrode current collector 400 is welded to the bottom of the steel shell. Further, the negative electrode lug is welded to the negative electrode current collector 400 by resistance welding. Further, the negative electrode lug has a second flattened structure, and the second flattened structure is welded to the negative electrode current collector 400, so that the negative electrode lug is welded to the negative electrode current collector 400.

[0095] See also Figure 3 In one embodiment, the cap 120 includes a sealing element 122, a conductive explosion-proof component 124, and a top cover 126. The sealing element 122 is sealed to the peripheral wall of the opening of the housing 110, so that the cap 120 covers the housing 110. The sealing element 122 covers the periphery of the conductive explosion-proof component 124, which is connected to the top cover 126. The conductive explosion-proof component 124 is electrically connected to the positive electrode tab, so that the conductive explosion-proof component 124 is electrically connected to both the top cover 126 and the positive electrode tab. The top cover 126 has a vent 1261. When the internal air pressure of the lithium-ion battery 10 reaches a first predetermined value, the conductive explosion-proof component 124 is pressed upward and folds up, so that the conductive explosion-proof component 124 is no longer electrically connected to the positive electrode tab, thereby creating an open circuit inside the lithium-ion battery 10 and improving the safety of the lithium-ion battery 10. In this embodiment, the conductive explosion-proof component 124 is electrically connected to the positive omnipolar tab via an electrical connection structure.

[0096] See also Figure 3In one embodiment, the conductive explosion-proof assembly 124 includes a conductive explosion-proof component 1242, an insulating pad 1244, and a safety valve 1246. The conductive explosion-proof component 1242 is connected to the top cover 126 and is electrically connected to the positive omnidirectional lug. The periphery of the safety valve 1246 is connected to the conductive explosion-proof component 1242 via the insulating pad 1244. The safety valve 1246 abuts against the conductive explosion-proof component 1242 and is electrically connected to the positive omnidirectional lug. In this embodiment, the safety valve 1246 is electrically connected to the positive omnidirectional lug via an electrical connection structure. When the internal pressure of the lithium-ion battery 10 reaches a first predetermined value, the conductive explosion-proof component 1242 is pressed upward and folds up, so that the conductive explosion-proof component 1242 and the safety valve 1246 are separated by the insulating pad 1244. That is, the conductive explosion-proof component 1242 and the safety valve 1246 are disconnected from each other and are in an insulated connection state, thereby making the conductive explosion-proof component 124 no longer electrically connected to the positive electrode tab, thus creating an open circuit inside the lithium-ion battery 10 and improving the safety of the lithium-ion battery 10. Furthermore, the projection of the safety valve 1246 onto the insulating pad 1244 is the projected outline of the safety valve 1246. The diameter of the projected outline of the safety valve 1246 is smaller than the peripheral diameter of the insulating pad 1244, and the peripheral edge of the insulating pad 1244 surrounds the projected outline of the safety valve 1246, creating a distance between the projected outline of the safety valve 1246 and the peripheral edge of the insulating pad 1244. This allows the safety valve 1246 to be connected to the conductive explosion-proof component 1242 through the insulating pad 1244, and the safety valve 1246 is reliably insulated from the conductive explosion-proof component 1242 when it is pressed and folded upwards. Even further, the conductive explosion-proof component 1242 has a pressure-bearing folding portion 1243, which is conical in shape, and its bottom abuts against the safety valve 1246, making the conductive explosion-proof component 1242 and the safety valve 1246 conduct electricity through contact. When subjected to a predetermined pressure, the pressure-bending part folds upward, separating the conductive explosion-proof component 1242 from the safety valve 1246. This disconnects the conductive explosion-proof component 1242 from the safety valve 1246, providing a better explosion-proof effect and improving the safety of the lithium-ion battery 10.

[0097] See also Figure 3 Furthermore, the safety valve 1246 has an explosion-proof opening groove 1246a and an explosion-proof crack opening 1246b. The explosion-proof crack opening and the explosion-proof opening groove are correspondingly arranged, and the explosion-proof crack opening and the explosion-proof opening groove are respectively located on both sides of the safety valve 1246. When the internal gas pressure of the lithium-ion battery 10 reaches a predetermined safety value, which is less than a first predetermined value, the safety valve 1246 cracks at the explosion-proof crack opening, causing the mounting valve to bulge upward and crack at the inner wall of the explosion-proof opening groove, thus giving the lithium-ion battery better explosion-proof performance. If the internal gas pressure of the lithium-ion battery 10 further increases, the pressure-bent part folds upward, causing the pressure-bent part to completely abut and separate from the safety valve, achieving a reliable power-off effect.

[0098] See also Figure 3 In one embodiment, the lithium-ion battery 10 further includes a positive electrode current collector 300, which is welded to the positive electrode tab and the safety valve 1246 respectively, so that the positive electrode tab is reliably electrically connected to the safety valve 1246 through the positive electrode current collector 300.

[0099] In one embodiment, the positive electrode current collector 300 has an electrical connection structure, which is welded to the safety valve 1246, thus welding the positive electrode current collector 300 to the safety valve 1246. In another embodiment, the positive electrode current collector 300 includes a current collector body and an electrical connection structure. The current collector body has a stamped groove, one end of the electrical connection structure is located in the stamped groove and connected to the current collector body, and the other end of the electrical connection structure is welded to the safety valve 1246, so that both ends of the electrical connection structure are reliably electrically connected to the current collector body and the safety valve 1246 respectively. At the same time, this makes the processing and forming of the tab structure formed by the positive electrode current collector 300 easier, and makes the structure of the lithium-ion battery 10 more compact. Specifically, the electrical connection structure is welded to the safety valve 1246, and the main body of the positive current collector 300 is welded to the positive full electrode tab. Since the electrical connection structure is connected to the main body of the positive current collector 300, the positive current collector 300 is welded to the safety valve 1246 and the positive full electrode tab respectively, so that the positive full electrode tab is reliably electrically connected to the safety valve 1246.

[0100] See also Figure 3 In one embodiment, an explosion-proof cracking region 1242a is formed on the conductive explosion-proof component 124. This region is designed to crack under a predetermined pressure, causing the conductive explosion-proof component 124 to fold upwards when the internal pressure of the lithium-ion battery 10 reaches a first predetermined value, thus separating the conductive explosion-proof component 124 from the safety valve 1246. If the internal pressure of the lithium-ion battery 10 further increases, i.e., if the internal pressure reaches a predetermined pressure (i.e., a second predetermined value), and the second predetermined value is greater than the first predetermined value, the conductive explosion-proof component 124 cracks in the explosion-proof cracking region to release pressure, ensuring the safety of the lithium-ion battery 10. In one embodiment, the outline of the explosion-proof cracking region is circular, triangular, quadrilateral, or polygonal. And / or, in one embodiment, the explosion-proof cracking region is a groove structure, simplifying its structure. It is understood that in other embodiments, the explosion-proof cracking region is not limited to a groove structure. For example, the explosion-proof cracking zone can also be a stress-concentrated spot-welded structure, so that the explosion-proof cracking zone automatically cracks when the internal gas pressure of the lithium-ion battery 10 reaches a second predetermined value, thus achieving a better explosion-proof effect.

[0101] See also Figure 3Furthermore, the top cover 126 has a vent 126a, which is correspondingly provided to the explosion-proof crack zone. When the explosion-proof crack zone cracks, the conductive explosion-proof component 124 can reliably release pressure after the explosion-proof crack zone cracks, further ensuring the safety of the lithium-ion battery 10.

[0102] like Figure 1 and Figure 4 As shown, this application also provides a manufacturing process for a lithium-ion battery 10, used to manufacture the lithium-ion battery 10 described in any of the above embodiments. Further, the manufacturing process for the lithium-ion battery 10 includes providing a casing 110 and a cap 120; the manufacturing process also includes:

[0103] S101, forming a core, the main component of the positive electrode active material of the core electrode sheet is lithium manganese oxide.

[0104] See also Figure 2 In this embodiment, the core 200 is formed. The main component of the positive electrode active material of the core 200 is lithium manganese oxide, that is, in addition to lithium manganese oxide, the positive electrode active material also contains a small amount of other substances.

[0105] S103, positive electrode tab structure and negative electrode tab structure are formed at both ends of the core respectively.

[0106] S105, place the core into the receiving slot of the housing.

[0107] See also Figures 2 to 3 In this embodiment, the core 200 is placed in the receiving groove of the housing 110, that is, the core 200 is placed inside the housing 110. The housing 110 is made of iron alloy, and the thermal conductivity of iron alloy is 36W / (m.℃)~60W / (m.℃).

[0108] S107, the negative electrode full-tab structure is connected to the housing through the negative electrode current collector, so that the negative electrode full-tab structure is used to electrically connect to the housing through the negative electrode current collector.

[0109] In this embodiment, the negative electrode omnipolar structure is connected to the housing 110 via the negative electrode current collector 400, so that the negative electrode omnipolar structure is used to electrically connect with the housing 110 via the negative electrode current collector 400, while the core 200 is fixedly positioned inside the housing 110.

[0110] S109, inject electrolyte into the receiving tank.

[0111] S111, the positive electrode tab structure is connected to the cap through the positive electrode current collector, so that the positive electrode tab structure can be electrically connected to the cap through the positive electrode current collector.

[0112] S113, the cap is sealed at the opening of the housing.

[0113] In this embodiment, the cap 120 is sealed at the opening of the housing 110, so that the lithium-ion battery 10 forms a sealed structure.

[0114] The aforementioned manufacturing method of the lithium-ion battery 10, because the positive electrode active material of the core 200 is mainly composed of lithium manganese oxide, gives the lithium-ion battery 10 a better energy density. Furthermore, because the core 200 has full-tab structures at both ends, one full-tab structure is electrically connected to the cap 120 through the positive current collector 300, and the other full-tab structure is directly electrically connected to the casing 110 through the negative current collector 400. This allows for rapid conduction of electricity within the lithium-ion battery 10, reducing resistance loss and heat generation, thus avoiding excessive internal heat generation. It also prevents the formation of hydrofluoric acid within the casing 110 due to the positive electrode active material, and allows for better compatibility with... The heat dissipation performance of the iron alloy casing 110 improves the safety performance of the lithium-ion battery 10, ensures the stability of the internal conductive potential of the lithium-ion battery 10, and enhances the conductivity reliability of the lithium-ion battery 10. Since the thermal conductivity of iron alloy is 36 W / (m·℃) ~ 60 W / (m·℃), the casing 110 has good heat dissipation performance. Furthermore, because the casing 110 is made of iron alloy, it has good structural strength, thus ensuring high structural safety of the lithium-ion battery 10. In this way, while improving the energy density, heat dissipation, and safety of the lithium-ion battery 10, especially for large-capacity lithium-ion batteries 10, the manufacturing cost of the lithium-ion battery 10 is effectively reduced.

[0115] In one embodiment, the step of forming the core 200 includes: firstly, forming a positive electrode sheet and a negative electrode sheet respectively, wherein the main component of the positive electrode active material of the positive electrode sheet is lithium manganese oxide, and at least one side of the positive electrode sheet has an aluminum foil empty area, and at least one side of the negative electrode sheet has a copper foil empty area; then, the positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and wound to form the core 200. In this embodiment, when stacking the positive electrode sheet, the separator, and the negative electrode sheet, the aluminum foil empty area of ​​the positive electrode sheet and the copper foil empty area of ​​the negative electrode sheet are staggered, that is, the aluminum foil empty area of ​​the positive electrode sheet is aligned with one side of the separator along the winding direction, and the copper foil empty area of ​​the negative electrode sheet is aligned with the other side of the separator along the winding direction. This staggered arrangement of the aluminum foil empty area and the copper foil empty area allows the two ends of the core 200 to be formed with a positive electrode tab structure and a negative electrode tab structure respectively.

[0116] Furthermore, the specific steps for forming positive electrode tab structures and negative electrode tab structures at both ends of the core 200 are as follows: the empty aluminum foil area and the empty copper foil area of ​​the core 200 are flattened respectively, so that the empty aluminum foil area forms a positive electrode tab structure and the empty copper foil area forms a negative electrode tab structure. This makes it easy to form positive electrode tab structures and negative electrode tab structures at both ends of the core 200, and at the same time makes the positive electrode tab structures and negative electrode tab structures relatively flat, so that the positive electrode tab structure can be connected to the positive electrode current collector 300 and the negative electrode tab structure can be connected to the negative electrode current collector 400.

[0117] In one embodiment, the steps of forming the positive electrode sheet and the negative electrode sheet are as follows: First, a first layer structure with positive active material is coated and formed on aluminum foil to form a positive electrode semi-finished product, so that there is an aluminum foil void area between the edge of the aluminum foil and the edge of the first layer structure; second, a second layer structure with negative active material is coated and formed on copper foil to form a negative electrode semi-finished product, so that there is a copper foil void area between the edge of the copper foil and the edge of the second layer structure; finally, the positive electrode semi-finished product and the negative electrode semi-finished product are respectively rolled to reliably form the first layer structure on the aluminum foil, and at the same time reliably form the second layer structure on the copper foil.

[0118] In one embodiment, there are two empty aluminum foil areas and two empty copper foil areas. The two empty aluminum foil areas are formed on both sides of the first layer structure, and the two empty copper foil areas are formed on both sides of the second layer structure. Further, after the step of rolling the positive electrode semi-finished product and the negative electrode semi-finished product respectively, the method further includes: slitting the rolled positive electrode semi-finished product and the negative electrode semi-finished product respectively, thus forming two positive electrode strips and two negative electrode strips.

[0119] In one embodiment, before the step of placing the core 200 into the receiving groove of the housing 110, and after the step of forming a positive electrode tab structure and a negative electrode tab structure at both ends of the core 200 respectively, the manufacturing process further includes: welding the positive electrode tab structure to the positive electrode current collector 300, and welding the negative electrode tab structure to the negative electrode current collector 400, so that the positive electrode tab structure is reliably electrically connected to the positive electrode current collector 300, and at the same time, the negative electrode tab structure is reliably electrically connected to the negative electrode current collector 400.

[0120] Further, the step of connecting the negative electrode tab structure to the housing 110 via the negative electrode current collector 400 specifically involves welding the negative electrode current collector 400 to the housing 110, thereby reliably positioning and connecting the negative electrode current collector 400 to the housing 110. Even further, the step of connecting the positive electrode tab structure to the cap 120 via the positive electrode current collector 300 specifically involves welding the positive electrode current collector 300 to the cap 120, thereby reliably electrically connecting the positive electrode current collector 300 to the cap 120. In this embodiment, the step of welding the positive electrode current collector 300 to the cap 120 specifically involves using laser welding to weld the positive electrode current collector 300 to the cap 120, thereby reliably connecting the positive electrode current collector 300 to the cap 120.

[0121] Furthermore, before the step of injecting electrolyte into the receiving tank, and after the step of connecting the negative electrode tab structure to the housing via the negative electrode current collector, the manufacturing process further includes: stamping the positive electrode current collector to form an electrical connection structure on the positive electrode current collector. The step of welding the positive electrode current collector to the cap specifically involves: welding the electrical connection structure to the cap, so that the positive electrode tab structure is better welded to the cap via the current collector, thereby better electrically connecting the positive electrode tab structure to the cap via the current collector. In this embodiment, the positive electrode current collector 300 includes a current collector body 310 and an electrical connection structure 320. The current collector body 310 has a stamped groove 312. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the cap, so that the electrical connection structure is reliably electrically connected to the current collector body and the cap respectively. This also makes the processing and forming of the tab structure formed by the positive electrode current collector 300 less difficult, thereby making the structure of the lithium-ion battery 10 more compact. And / or,

[0122] Furthermore, after the step of welding the negative current collector to the housing and before the step of injecting electrolyte into the receiving tank, the manufacturing process further includes: grooving the housing to define the position of the core, so that the core is reliably installed and confined within the housing.

[0123] In one embodiment, after the step of sealing the cap 120 at the opening of the housing 110, the manufacturing process further includes: performing a formation process on the battery cell. In this embodiment, the step of performing a formation process on the battery cell specifically involves: performing a sealing formation process on the battery cell, followed by selection and capacity testing to obtain the finished product.

[0124] Furthermore, before the step of sealing the cap 120 at the opening of the housing 110, and after the step of placing the core 200 in the receiving groove, the manufacturing process further includes: performing an insulating coating treatment on the periphery where the positive electrode tab structure connects to the positive electrode current collector 300, so that the positive electrode current collector 300 is insulated from the housing 110, thus forming an insulating coating structure 500 at the connection between the positive electrode current collector 300 and the positive electrode tab. This insulating coating structure 500 covers the periphery where the positive electrode tab structure connects to the positive electrode current collector 300, ensuring a reliable insulating connection between the positive electrode tab structure and the positive electrode current collector 300, and preventing a short circuit caused by direct contact between the positive electrode tab structure and the positive electrode current collector 300. See also... Figures 2 to 3 Furthermore, the insulating covering structure 500 includes an adhesive layer 510 and an insulating sheet 520. The adhesive layer 510 is bonded to the end of the positive electrode tab structure. The positive electrode current collector 300 is fixed to the end face of the positive electrode tab structure through the adhesive layer 510. The insulating sheet 520 is sleeved at the connection between the positive electrode tab structure and the positive electrode current collector 300, and the insulating sheet 520 is fixed on the adhesive layer 510, so that the insulating covering structure 500 covers the periphery of the connection between the positive electrode tab structure and the positive electrode current collector 300. Furthermore, the step of insulating the periphery where the positive electrode tab structure connects to the positive electrode current collector 300 includes: bonding an adhesive layer 510 to the surface of the positive electrode current collector 300 facing away from the positive electrode tab structure and to the sidewall of the end of the positive electrode tab structure; fitting an insulating sheet 520 onto the connection between the positive electrode tab structure and the positive electrode current collector 300, and bonding the insulating sheet 520 to the adhesive layer 510, with a portion of the adhesive layer 510 exposed on the sidewall of the end of the positive electrode tab structure, so that the core 200 can be bonded to the housing 110 for pre-fixed positioning after being inserted into the housing, facilitating subsequent welding of the negative electrode current collector 400 to the inner wall of the housing 110, and improving the welding accuracy of the negative electrode current collector 400 to the housing 110.

[0125] See also Figures 2 to 3 In this embodiment, the adhesive layer 510 is coated and formed on the end face and outer peripheral wall of the positive electrode tab structure. Furthermore, the insulating sheet 520 has exposed areas, exposing a portion of the positive electrode current collector 300 to external conductivity. Further still, the adhesive layer 510 is partially exposed outside the insulating sheet 520, and is also adhered to the inner wall of the housing 110, ensuring the core 200 is reliably installed and positioned within the housing 110.

[0126] See also Figures 2 to 3Furthermore, before the step of sealing the cap 120 at the opening of the housing 110, and after the step of performing insulation coating treatment at the periphery where the positive electrode tab connects to the positive electrode current collector 300, the manufacturing process further includes: grooving the housing 110 and baking the welded battery cell. After grooving the housing 110, a pressure groove 112 is formed near the opening of the housing 110, confining the core 200 within the receiving groove, thereby reliably fixing the core 200 within the housing 110 and reducing the moisture inside the battery cell. In this embodiment, before rolling the housing 110, the electrical connection structure of the positive electrode current collector 300 is separated from the housing 110 so that the electrical connection structure leads out to the insulation coating structure 500.

[0127] It is understood that in other embodiments, the formation process of the battery cell specifically involves performing formation processing on the battery cell using an open-cell formation process. In one embodiment, the steps of performing formation processing on the battery cell using an open-cell formation process include: first, allowing the sealed battery to stand and be immersed in electrolyte; then, removing the formation pin from the vent hole of the explosion-proof cap 120; then, performing negative pressure formation on the battery; finally, after the battery has undergone formation and venting, sealing the negative pressure formation vent hole with a sealing pin and laser welding the seal. Because the open-cell formation process uses a cap 120 with a top-cap-less design and no explosion-proof aluminum sheet edging, the structure of the cap 120 is simpler, making the manufacturing process of the cap 120 simpler and less expensive.

[0128] like Figure 5 As shown, in one embodiment, the cap 120 includes an explosion-proof cover 120a, an insulating washer 120b, a connecting piece 120c, a formation pin (not shown), a sealing pin (not shown), and a sealing ring 120d. The sealing ring covers the explosion-proof cover and is laser-welded to the opening of the housing 110, thereby sealing the housing 110. The explosion-proof cover has a vent hole 1201, and the sealing ring has a corresponding clearance hole 1203. The formation pin is located in the vent hole and connected to the explosion-proof cover. The formation pin is used to be pulled out of the explosion-proof cover during formation. The sealing pin is used to be located in the vent hole after formation and welded to the explosion-proof cover to seal the vent hole, thus achieving the degassing effect of negative pressure formation. The connecting piece is electrically connected to the electrical connection structure. Furthermore, the connecting piece is welded to the electrical connection structure to ensure a reliable electrical connection between the connecting piece and the electrical connection structure.

[0129] like Figure 5As shown, the explosion-proof cover 120a further includes a flip-up flange structure 1205 and a positioning groove 1206. An insulating gasket covers the connecting piece and is located within the positioning groove, connecting to the explosion-proof cover. A portion of the connecting piece is exposed above the insulating gasket, and a pressure relief hole 1207 communicating with the receiving groove is formed at the exposed portion of the connecting piece. The exposed portion of the connecting piece also abuts against the flip-up flange structure for electrical conduction. The pressure relief hole and the flip-up flange structure are correspondingly positioned. When the internal gas pressure of the battery reaches a first predetermined value, the flip-up flange structure flips upward to disconnect the connection between the connecting piece and the flip-up flange structure, providing power-off protection and achieving negative pressure formation and degassing, while simultaneously fulfilling the functions of power-off protection and explosion-proof protection.

[0130] To further improve battery safety performance, such as Figure 5 As shown, the flip-flange structure 1205 further includes a first explosion-proof groove 1208. When the internal pressure of the battery increases further and reaches a second predetermined value, the flip-flange structure cracks at the first explosion-proof groove, reliably releasing pressure and further improving the battery's safety performance. In one embodiment, the first explosion-proof groove is circular, triangular, quadrilateral, or polygonal. To further improve the rate of pressure release, especially when the internal pressure increases rapidly, a pressure relief groove 1209 is formed on the part of the connecting piece 120c exposed to the insulating gasket, and the pressure relief groove communicates with the receiving groove. The connecting piece 120c has a second explosion-proof etched line 1211, which corresponds to the pressure relief groove. When the internal pressure of the battery increases rapidly, the connecting piece cracks at the second explosion-proof etched line, allowing the internal pressure to be released simultaneously through the pressure relief groove and the pressure relief hole, thus improving the pressure relief speed, especially when the internal pressure increases rapidly. This multi-layered explosion-proof design greatly improves the battery's safety performance, particularly for large cylindrical batteries. In one embodiment, the second explosion-proof etched groove is circular, triangular, quadrilateral, or polygonal.

[0131] This application also provides a battery module, including a lithium-ion battery 10 prepared according to the manufacturing process of the lithium-ion battery 10 in any of the above embodiments.

[0132] In one embodiment, the battery module further includes a battery mounting bracket, to which the housing 110 is mounted and fixed, thereby reliably assembling and fixing the lithium-ion battery 10 to the battery mounting bracket. In one embodiment, a pressure groove is formed on the outer peripheral wall of the housing 110, and a limiting flange is formed on the inner peripheral wall of the housing 110 at a position corresponding to the pressure groove, thereby limiting the winding core 200 within the receiving groove. The battery mounting bracket has an assembly protrusion located within the pressure groove and abutting against the housing 110, thereby reliably assembling and fixing the lithium-ion battery 10 to the battery mounting bracket. In this embodiment, there are multiple assembly protrusions and multiple lithium-ion batteries 10, with each assembly protrusion corresponding to and positioned within a pressure groove of a multiple lithium-ion battery 10, making the structure of the assembled battery module more compact.

[0133] Compared with the prior art, the present invention has at least the following advantages:

[0134] 1. The lithium-ion battery 10 described above has good energy density because the positive active material of the core 200 is mainly lithium manganese oxide. Furthermore, the core 200 has full-tab structures at both ends. One full-tab structure is electrically connected to the cap 120 via the positive current collector 300, and the other full-tab structure is electrically connected to the casing 110 via the negative current collector 400. This allows for rapid heat dissipation when the lithium-ion battery 10 is conducting electricity, avoiding excessive internal heat generation. It also prevents the positive active material from easily generating hydrofluoric acid within the casing 110 and better adapts to the heat dissipation performance of the iron alloy casing 110. This improves the safety performance of the lithium-ion battery 10, ensures low contact resistance between internal active materials, avoids easy battery failure, and enhances the conductivity reliability of the lithium-ion battery 10.

[0135] 2. Due to the thermal conductivity of iron alloys being 36W / (m.℃) to 60W / (m.℃), the casing 110 has good heat dissipation performance. Furthermore, since the casing 110 is made of iron alloy, it has good structural strength, thereby improving the structural safety of the lithium-ion battery 10. Thus, while improving the energy density, heat dissipation, and safety of the lithium-ion battery 10, especially for large-capacity lithium-ion batteries 10, the manufacturing cost of the lithium-ion battery 10 is effectively reduced.

[0136] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A lithium-ion battery, comprising a casing and a winding core, the casing comprising a housing and a cap, the cap being disposed on the housing, the winding core being housed within the housing and electrically connected to both the cap and the housing, the housing containing an electrolyte impregnating the winding core; characterized in that, The shell is made of iron alloy, and the thermal conductivity of the iron alloy is 36W / (m.℃)~60W / (m.℃). The main component of the positive electrode active material of the core electrode sheet is lithium manganese oxide; The core is provided with a positive electrode tab structure and a negative electrode tab structure at both ends. The positive electrode tab structure is used to be electrically connected to the cap through the positive electrode current collector, and the negative electrode tab structure is used to be electrically connected to the shell through the negative electrode current collector. The lithium manganese oxide content of the positive electrode active material is 60% to 100%. The electrical parameters of the lithium-ion battery are as follows: voltage of 2.75V~4.2V, capacity of 8 Ah~80Ah, and resistance of 0.8mΩ~4mΩ; The lithium-ion battery has a current of 950mA to 28000mA.

2. The lithium-ion battery of claim 1, wherein, The proportion of lithium manganese oxide in the positive electrode active material is 70%~90%.

3. The lithium-ion battery of claim 1, wherein, The shell is a one-piece stamped structure.

4. The lithium-ion battery according to claim 3, characterized in that, The shell is made of steel, with a height of 110 mm to 220 mm and a diameter of 30 mm to 60 mm.

5. The lithium-ion battery of claim 3, wherein, The lithium-ion battery model is 4680, 34145, 60220, or 30110.

6. The lithium-ion battery of claim 1, wherein, The thermal conductivity of the iron alloy is 45 W / (m·℃), and the resistivity of the iron alloy is 10 × 10⁻⁸ Ω·m.

7. The lithium-ion battery of claim 1, wherein, The positive current collector is made of aluminum, and the negative current collector is made of nickel; and / or, The surface of the housing is coated with a nickel layer.

8. The lithium-ion battery of claim 1, wherein, The positive electrode tab is welded to the positive electrode current collector.

9. The lithium-ion battery according to claim 8, characterized in that, It also includes an insulating covering structure, which covers the periphery where the positive electrode tab structure connects to the positive electrode current collector.

10. The lithium-ion battery of claim 1, wherein, The positive current collector has an electrical connection structure, which is electrically connected to the cap.

11. The lithium-ion battery of claim 10, wherein, The positive current collector includes a current collector body and the electrical connection structure. The current collector body has a stamped groove. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the cap.

12. The lithium-ion battery of claim 11, wherein, The positive current collector is formed with the electrical connection structure through a stamping process; and / or The lithium-ion battery also includes an insulating covering structure, which covers the periphery where the positive electrode tab connects to the positive electrode current collector, and the insulating covering structure is arranged around the positive electrode current collector.

13. The lithium-ion battery of claim 1, wherein, The negative electrode tab is welded to the negative electrode current collector, and the negative electrode current collector is welded to the housing.

14. The lithium-ion battery of claim 1, wherein, The cap includes a sealing element, a conductive explosion-proof component, and a top cover. The sealing element is sealed to the peripheral wall of the opening of the housing. The sealing element covers the periphery of the conductive explosion-proof component. The conductive explosion-proof component is connected to the top cover. The conductive explosion-proof component is electrically connected to the positive electrode lug. The top cover has an air vent.

15. The lithium-ion battery of claim 14, wherein, The conductive explosion-proof assembly includes a conductive explosion-proof component, an insulating pad, and a safety valve. The conductive explosion-proof component is connected to the top cover and is electrically connected to the positive omnidirectional lug. The periphery of the safety valve is connected to the conductive explosion-proof component through the insulating pad. The safety valve abuts against the conductive explosion-proof component and is electrically connected to the positive omnidirectional lug.

16. The lithium-ion battery of claim 15, wherein, The lithium-ion battery also includes a positive electrode current collector, which is welded to the positive electrode tab and the safety valve respectively.

17. The lithium-ion battery of claim 16, wherein, The positive current collector has an electrical connection structure, which is welded to the safety valve.

18. The lithium-ion battery of claim 17, wherein, The positive current collector includes a current collector body and the electrical connection structure. The current collector body has a stamped groove. One end of the electrical connection structure is located in the stamped groove and connected to the current collector body. The other end of the electrical connection structure is welded to the safety valve.

19. The lithium-ion battery of claim 14, wherein, The conductive explosion-proof component has an explosion-proof crack zone formed on it, which is used to crack under a predetermined pressure.

20. The lithium-ion battery of claim 19, wherein, The explosion-proof cracking zone has a circular, triangular, quadrilateral, or polygonal outline; and / or, the explosion-proof cracking zone is a groove structure.

21. A process for manufacturing a lithium-ion battery, comprising providing a casing and a cap; characterized in that, The preparation process further includes: A core is formed, wherein the main component of the positive electrode active material of the core electrode sheet is lithium manganese oxide; Positive electrode tab structure and negative electrode tab structure are respectively formed at both ends of the winding core; The core is placed in the receiving slot of the housing; The negative electrode omnipolar structure is connected to the housing via a negative electrode current collector, so that the negative electrode omnipolar structure is used to electrically connect to the housing via the negative electrode current collector. Electrolyte is injected into the receiving tank; The positive electrode omnipolar structure is connected to the cap via a positive electrode current collector, so that the positive electrode omnipolar structure is electrically connected to the cap via the positive electrode current collector; The cap is sealed at the opening of the housing; The shell is made of an iron alloy, and the thermal conductivity of the iron alloy is 36 W / (m·℃) to 60 W / (m·℃).

22. The process for the preparation of a lithium-ion battery according to claim 21, characterized in that, The step of forming the core includes: A positive electrode sheet and a negative electrode sheet are formed separately, wherein the main component of the positive electrode active material of the positive electrode sheet is lithium manganese oxide, and an aluminum foil empty foil area is formed on at least one side of the positive electrode sheet, and a copper foil empty foil area is formed on at least one side of the negative electrode sheet. The positive electrode, the separator, and the negative electrode are sequentially stacked and wound to form a core; The specific steps of forming a positive electrode tab structure and a negative electrode tab structure at both ends of the core are as follows: flattening the empty aluminum foil area and the empty copper foil area of ​​the core respectively, so that the empty aluminum foil area forms the positive electrode tab structure and the empty copper foil area forms the negative electrode tab structure.

23. The process for the preparation of a lithium-ion battery according to claim 22, characterized in that, The specific steps for forming the positive and negative electrode sheets are as follows: A first layer structure with the positive electrode active material is formed by coating aluminum foil to form a positive electrode semi-finished product, such that there is an aluminum foil void area between the edge of the aluminum foil and the edge of the first layer structure. A second layer structure with a negative electrode active material is formed by coating copper foil to form a negative electrode semi-finished product, such that there is a copper foil void area between the edge of the copper foil and the edge of the second layer structure. The positive electrode semi-finished product and the negative electrode semi-finished product are respectively subjected to rolling operations.

24. The process for the fabrication of a lithium-ion battery according to claim 21, characterized in that, Before the step of placing the winding core into the receiving groove of the housing, and after the step of forming the positive electrode tab structure and the negative electrode tab structure at both ends of the winding core respectively, the manufacturing process further includes: The positive electrode omnipolar structure is welded to the positive electrode current collector, and the negative electrode omnipolar structure is welded to the negative electrode current collector; The step of connecting the negative electrode omnipolar structure to the housing via the negative electrode current collector plate specifically involves welding the negative electrode current collector plate to the housing. The specific step of connecting the positive electrode omnipolar structure to the cap via the positive electrode current collector is as follows: welding the positive electrode current collector to the cap.

25. The process for the preparation of a lithium-ion battery according to claim 24, characterized in that, in Before the step of injecting electrolyte into the receiving tank, and after the step of connecting the negative electrode omnipolar structure to the housing via the negative electrode current collector, the manufacturing process further includes: stamping the positive electrode current collector to form an electrical connection structure on the positive electrode current collector; The step of welding the positive current collector to the cap specifically includes: welding the electrical connection structure to the cap; and / or... After the step of welding the negative electrode current collector to the housing, and before the step of injecting electrolyte into the receiving tank, the manufacturing process further includes: The housing is grooved to define the position of the winding core.

26. A battery module comprising: The invention includes a lithium-ion battery, which is prepared by the process described in any one of claims 21 to 25.

27. The battery module of claim 26, wherein, It also includes a battery mounting bracket, and the housing is mounted and fixed to the battery mounting bracket.

28. The battery module of claim 27, wherein, The outer peripheral wall of the housing has a crimping groove, and the inner peripheral wall of the housing has a limiting flange at the position corresponding to the crimping groove, so that the winding core is limited to the receiving groove. The battery fixing bracket has an assembly protrusion, which is located in the crimping groove and abuts against the housing.

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