Lithium battery and manufacturing method thereof

Abstract

The invention provides a lithium battery and a manufacturing method thereof.The lithium battery comprises a shell, the shell is provided with an opening, a positive electrode groove and a negative electrode groove which are separated by a diaphragm are formed in the shell, and the cross section area of the negative electrode groove is larger than that of the positive electrode groove when viewed in the arrangement direction of the positive electrode groove and the negative electrode groove; a positive electrode material and a negative electrode material are respectively arranged in the positive electrode groove and the negative electrode groove; the conductive parts comprise a positive electrode conductive part and a negative electrode conductive part, and at least part of the positive electrode conductive part and the negative electrode conductive part extend in the height direction of the shell and are arranged in the positive electrode groove and the negative electrode groove respectively; confluence plates are arranged on the confluence plate at intervals, and the confluence plates are connected with the positive electrode conductive piece and the negative electrode conductive piece respectively; and the cover plate is arranged at the opening and is respectively connected with the shell and the confluence sheet, so that the conductive piece and the confluence plate are sealed between the shell and the cover plate. According to the invention, the processing procedures of the lithium battery can be reduced, the processing difficulty is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a lithium battery and a manufacturing method thereof. Background Art

[0002] Existing lithium batteries include various structures such as positive and negative electrode plates, separators, connecting plates, top covers, aluminum shells, sealing nails, etc. There are various problems in manufacturing various battery structures. For example, at least 30 processes are required for sheet making and assembly, and more than 10 types of large-scale processing equipment are needed, such as coating machines, rolling presses, die-cutting machines, winding machines, baking equipment, liquid injection machines, etc. The length of the production line in the manufacturing factory is up to more than 500m. Moreover, there are processes with high processing difficulty in the manufacturing of existing lithium batteries, and various problems that affect the battery quality are likely to occur during processing. For example, the manufacturing consistency of the electrolytic copper foil thickness is poor, the yield of the rolled aluminum foil is low, the consistency of the electrode sheet coating process is poor, the thick coating process of the electrode sheet is difficult, the high-compaction electrode sheet is prone to breakage during rolling, the misalignment rate of the winding tabs is high, the misalignment rate of the stacked sheets is high, the Hi-pot failure caused by metal foreign matter mixing during slitting, die-cutting and processing, the high-difficulty high-energy laser welding, and it is difficult to reduce the moisture during baking. Summary of the Invention

[0003] In order to overcome the defects in the prior art, the embodiments of the present invention provide a lithium battery and a manufacturing method thereof, which can reduce the processing procedures of the lithium battery, reduce the processing difficulty, and reduce the production cost of the lithium battery.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] The first aspect of the present invention discloses a lithium battery, including:

[0006] A housing, the housing is provided with an opening, and a positive electrode slot and a negative electrode slot separated by a separator are arranged inside the housing. When viewed along the arrangement direction of the positive electrode slot and the negative electrode slot, the cross-sectional area of the negative electrode slot is larger than that of the positive electrode slot, and positive electrode material and negative electrode material are respectively arranged in the positive electrode slot and the negative electrode slot;

[0007] A conductive member, the conductive member includes a positive electrode conductive member and a negative electrode conductive member, and at least part of the positive electrode conductive member and the negative electrode conductive member extend along the height direction of the housing and are respectively arranged in the positive electrode slot and the negative electrode slot;

[0008] A bus bar, the bus bar is provided with bus bar pieces at intervals, and the bus bar pieces are respectively connected to the positive electrode conductive member and the negative electrode conductive member;

[0009] A cover plate, the cover plate is arranged at the opening and is respectively connected to the housing and the bus bar pieces, and the conductive member and the bus bar are enclosed between the housing and the cover plate.

[0010] In the above technical solution, the electrode material is directly arranged in the housing and conducts current through the conductive member for current collection. Compared with the winding core and electrolyte structure arranged in the existing lithium battery, this application does not require processes such as coating, rolling, die-cutting, winding or laminating, hot pressing, wrapping with Mylar film, pre-welding into the housing, baking the battery core, first liquid injection, high-temperature infiltration, and welding of the sealing nail. It can reduce the processing procedures of the lithium battery, reduce the production cost of the lithium battery, and significantly reduce the processing difficulty of the lithium battery.

[0011] Furthermore, a protrusion is provided on the inner surface of the housing, and the separator is connected to the protrusion, so that the separator and the protrusion enclose to form the positive electrode groove, and the separator and the housing enclose to form the negative electrode groove.

[0012] By the way that the separator and the housing enclose to form the positive electrode groove and the negative electrode groove, the separator is in contact with the positive electrode material and the negative electrode material. The separator does not need to be wound. Not only is the processing method simple, but also it can solve the problems of wavy edges, uneven tension, edge collapse, and wrinkling of the separator generated during the winding of the separator in the production of the existing winding core.

[0013] Furthermore, a groove is provided on the circumferential side of the opening of the housing, and a first sealing ring is arranged in the groove. The first sealing ring is used to seal the connection between the cover plate and the housing to ensure the sealing performance of the battery.

[0014] Even further, the housing is injection-molded. It can avoid the problem that metal chips of the existing metal housing enter the battery interior and cause battery short-circuit defects and the corrosion problem of the metal housing, and can reduce the process of wrapping the insulating film required for using the metal housing.

[0015] Furthermore, the positive electrode conductive member includes a positive electrode current collection grid arranged in a grid pattern. The positive electrode current collection grid is formed by a plurality of aluminum wires arranged along the length direction and the width direction of the housing and having intersections. The negative electrode conductive member includes a negative electrode current collection grid arranged in a grid pattern. The negative electrode current collection grid is formed by a plurality of copper wires arranged along the length direction and the width direction of the housing and having intersections.

[0016] By forming the current collection grid with the grid-shaped aluminum wires and copper wires for current conduction, it can reduce the current collection sheets arranged on the cover plate, reduce the process difficulty of the cover plate, and the processing difficulty of the aluminum wires and copper wires is low. It can reduce the rolling and coating processes, avoid the rolling and coating problems of copper foils and aluminum foils in the production of existing batteries, and can reduce the complexity of the lithium battery processing process and reduce the cost.

[0017] Further, the intersection of the positive electrode conductive busbar network is higher than the intersection of the negative electrode conductive busbar network. An insulating plate is provided between the intersection of the positive electrode conductive busbar network and the top intersection of the negative electrode conductive busbar network, and through holes for aluminum wires to pass through are provided on the insulating plate. The positive electrode conductive busbar network and the negative electrode conductive busbar network are separated by the insulating plate to prevent short - circuit between the positive and negative electrodes of the lithium - ion battery.

[0018] Further, the thickness of the separator is less than or equal to 0.3 mm, and at least one through hole is provided on the separator. The through hole is used for the electrolyte to flow through.

[0019] Further, ventilation holes are provided on the busbar. The ventilation holes are used for gases to pass through during the formation process.

[0020] Further, a terminal post and an explosion - proof hole are provided on the cover plate. A connecting piece is provided on the terminal post, the connecting piece is connected to the busbar piece, a detachable explosion - proof valve is provided in the explosion - proof hole, and a second sealing ring is provided outside the explosion - proof hole.

[0021] When the explosion - proof valve is installed in the explosion - proof hole, it can be used for explosion protection of the lithium - ion battery. When the explosion - proof valve is removed from the explosion - proof hole, formation and electrolyte supplementation can be carried out through the explosion - proof hole. With the detachable explosion - proof valve, the structure of the cover plate can be simplified, making the processing of the cover plate simpler.

[0022] The second aspect of the present invention discloses a method for manufacturing a lithium - ion battery, including the following steps:

[0023] Prepare a housing, and a separator is arranged in the housing to form a positive electrode groove and a negative electrode groove;

[0024] Prepare conductive parts, the conductive parts include a positive electrode conductive part and a negative electrode conductive part. In sequence, at least part of the negative electrode conductive part is arranged in the negative electrode groove, an insulating plate is arranged at the top of the negative electrode conductive part, and at least part of the positive electrode conductive part is passed through the insulating plate and arranged in the positive electrode groove;

[0025] Prepare electrode materials, the electrode materials include a positive electrode material and a negative electrode material, and the positive electrode material and the negative electrode material are respectively poured into the positive electrode groove and the negative electrode groove;

[0026] Prepare a busbar, and connect the positive electrode conductive part and the negative electrode conductive part to the busbar pieces on the busbar respectively;

[0027] Prepare a cover plate, after connecting the cover plate to the busbar, connect the cover plate to the housing;

[0028] Perform process treatment on the battery after connecting the cover plate to obtain the target lithium - ion battery.

[0029] By directly pouring the electrode material into the casing and conducting current collection through the conductive parts, compared with the existing lithium battery manufacturing method, this application does not require processes such as coating, rolling, die-cutting, winding or laminating, hot pressing, wrapping with Mylar film, pre-welding in the casing, baking the battery cell, primary liquid injection, high-temperature infiltration, and sealing nail welding. It can reduce 40% - 50% of the lithium battery processing procedures, save at least 70% of the equipment cost, save 40% - 50% of the lithium battery production site, and save at least 70% of the production line environmental control and equipment processing energy consumption. The manufacturing method of the lithium battery is simple, can significantly reduce the processing difficulty of the lithium battery, and improve the processing efficiency by at least 40%.

[0030] Further, the electrode material includes an active material, a conductive agent, a binder, and a solvent. The solvent is an electrolyte. The steps for preparing the electrode material include:

[0031] Dividing the electrolyte into a first electrolyte and a second electrolyte according to a preset amount, and the sum of the amounts of the first electrolyte and the second electrolyte is equal to the amount of the electrolyte;

[0032] Adding the first electrolyte to the mixture of the active material, the conductive agent, and the binder, and stirring at a preset temperature to make them fully mixed, thereby obtaining a first mixture;

[0033] Adding the second electrolyte to the first mixture, and stirring at a preset temperature to make them fully mixed, thereby obtaining the electrode material;

[0034] Pouring the electrode material into the casing and removing the gas mixed in the electrode material.

[0035] Using the electrolyte as the solvent of the electrode material, the mixture in the electrode material can be wetted by the electrolyte when preparing the electrode material, which can reduce the primary liquid injection process and avoid the problem of difficult electrolyte infiltration during primary liquid injection. Compared with the method of dissolving the mixture in the electrode material by NMP and ultrapure water when preparing the existing materials, it can reduce the material cost, does not require liquid injection equipment, NMP recovery equipment, and ultrapure water equipment, and the prepared material does not need to go through processes such as drying, coating, rolling, slicing, and winding, thereby reducing the production cost of the lithium battery and reducing the lithium battery processing procedures.

[0036] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0037] By directly pouring the electrode material into the housing and conducting current through the conductive parts for current collection, compared with the existing lithium battery manufacturing methods, this application does not require processes such as coating, rolling, die-cutting, winding or laminating, hot pressing, wrapping with Mylar film, pre-welding in the housing, baking the battery cell, primary liquid injection, high-temperature infiltration, and welding of the sealing nail. It can reduce the processing procedures of lithium batteries, save equipment costs and production sites, save the energy consumption for production line environment control and equipment processing, and has a simple processing method, which can significantly reduce the processing difficulty of lithium batteries and improve the processing efficiency.

[0038] To make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the accompanying drawings, makes a detailed description as follows. Brief Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a structural diagram of a housing provided by an embodiment of this application;

[0041] Figure 2 It is a connection structural diagram of a conductive current collection net provided by an embodiment of this application;

[0042] Figure 3 It is a partial top view of a conductive current collection net provided by an embodiment of this application;

[0043] Figure 4 It is a partial enlarged view of a conductive current collection net provided by an embodiment of this application;

[0044] Figure 5 It is a structural diagram of a current collection plate provided by an embodiment of this application;

[0045] Figure 6 It is a structural diagram of a cover plate provided by an embodiment of this application;

[0046] Figure 7 It is a connection structural diagram of a current collection plate and a cover plate provided by an embodiment of this application;

[0047] Figure 8 It is a structural diagram of an explosion-proof valve provided by an embodiment of this application;

[0048] Figure 9 It is a structural diagram of a battery provided by an embodiment of this application.

[0049] Reference numerals in the above drawings: 1. housing; 2. protrusion; 3. diaphragm; 4. positive electrode groove; 5. negative electrode groove; 6. positive electrode conductive member; 601. intersection of the top ends of the positive electrode conductive busbar network; 7. negative electrode conductive member; 701. intersection of the top ends of the negative electrode conductive busbar network; 8. busbar; 9. positive electrode busbar piece; 10. negative electrode busbar piece; 11. ventilation hole; 12. insulating plate; 13. through hole; 14. cover plate; 15. positive electrode terminal; 16. negative electrode terminal; 17. positive electrode connecting piece; 18. negative electrode connecting piece; 19. explosion-proof hole; 20. explosion-proof valve; 21. first sealing ring; 22. second sealing ring; 23. internal thread; 24. external thread; 25. explosion-proof film; 26. notch. Detailed implementation manners

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Additionally, it is stated in advance that the accompanying drawings of the present invention are only for simple schematic illustration and are not drawn according to actual dimensions.

[0051] In the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "frontward", "backward", "between", "close to", "far from", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. It should also be noted that unless otherwise clearly defined and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] It should be understood that although terms such as "first", "second", "third", etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another, or one signal from another. Additionally, the term "or" used herein may include any one or a combination of multiple of the associated listed items depending on the actual situation.

[0053] Referring to Figures 1 to 9 , an embodiment of the present application provides a lithium battery, which includes a housing 1, a conductive member and a busbar disposed inside the housing 1, and a cover plate 14 connected to the housing 1.

[0054] As Figure 1 andFigure 9 As shown, the housing 1 is provided with an opening. Inside the housing 1, a positive electrode groove 4 and a negative electrode groove 5 separated by a diaphragm 3 are provided. When viewed along the arrangement direction of the positive electrode groove 4 and the negative electrode groove 5, the cross-sectional area of the negative electrode groove 5 is larger than that of the positive electrode groove 4. Positive electrode material and negative electrode material are respectively provided in the positive electrode groove 4 and the negative electrode groove 5.

[0055] With the above structure, the lithium battery in the embodiment of the present application does not need to be provided with a wound core, thereby reducing multiple processes including coating, rolling, die cutting, winding or laminating, hot pressing, etc. required for preparing the wound core of the existing lithium battery, thereby being able to improve processing efficiency, reduce production costs and processing difficulties.

[0056] Specifically, in this embodiment, a protrusion 2 is provided on the inner surface of the housing 1. The diaphragm 3 is connected to the protrusion 2, so that the diaphragm 3 and the protrusion 2 enclose to form the positive electrode groove 4, and the diaphragm 3 and the housing 1 enclose to form the negative electrode groove 5. The protrusion 2 is arranged such that the volume of the positive electrode groove 4 is smaller than that of the negative electrode groove 5, so that the amount of the negative electrode material in the negative electrode groove 5 is larger than the amount of the positive electrode material in the positive electrode groove 4, satisfying the negative electrode capacity: positive electrode capacity > 1 (N:P > 1), thereby ensuring that the negative electrode of the lithium battery has sufficient capacity to receive the lithium ions released by the positive electrode during charging, thereby avoiding problems of lithium deposition and dead zones, and avoiding the situation where the positive electrode capacity is too large, the excess lithium ions cannot be completely embedded in the negative electrode during charging, and lithium deposits are formed on the surface of the negative electrode, resulting in the formation of dendrites, and avoiding causing an internal short circuit in the battery and affecting the cycle performance of the battery.

[0057] In some embodiments, the housing 1 can be set to be square, cylindrical or other shapes. At least one positive electrode groove 4 and at least one negative electrode groove 5 can be provided inside the housing 1. When multiple grooves are provided, the positive electrode grooves 4 and the negative electrode grooves 5 are alternately arranged.

[0058] Optionally, the housing 1 is made of a material resistant to hydrofluoric acid and is integrally formed by injection molding. Compared with the existing metal housing, it can avoid problems of battery short circuit caused by metal chips and corrosion of the metal housing due to the corrosion potential of the metal housing, and reduces the process of wrapping an insulating film required for using a metal housing.

[0059] In some embodiments, the housing 1 can be made of polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA) or other materials.

[0060] A groove is provided on the peripheral side of the opening of the housing 1. A first sealing ring 21 is provided in the groove. The first sealing ring 21 is used to seal the lower surface of the cover plate 14 when assembled with the cover plate 14. In some embodiments, the first sealing ring 21 is a sealing rubber ring, and rubber such as natural rubber, fluororubber, silicone rubber or other materials can be selected, or plastic and synthetic resin materials such as polyurethane, polytetrafluoroethylene or other materials can be selected, or metal and special composite materials can be selected.

[0061] To avoid the diaphragm having too large a thickness and occupying too much volume inside the housing, the thickness of the diaphragm 3 is less than or equal to 0.3 mm. When the diaphragm thickness is set within this range, it can avoid reducing the proportion of the electrode material inside the housing, thereby avoiding reducing the battery energy density, the lithium-ion migration rate, and the battery rate performance. At the same time, the minimum thickness of the diaphragm should be able to meet the support strength of the trough inside the housing to avoid the diaphragm collapsing and deforming, which affects the consistency of the electrode material thickness. The minimum thickness of the diaphragm can be set according to the actual situation, and this application does not make specific limitations here.

[0062] At least one through hole is provided on the diaphragm 3 to enable the electrolyte to flow during liquid replenishment.

[0063] In some embodiments, the through holes on the diaphragm 3 are micro holes in the order of hundreds of micrometers. The diaphragm 3 is made of PP or PE or a ceramic-coated material and is ultrasonically welded at the junction of the positive electrode trough 4 and the negative electrode trough 5. Compared with the diaphragm in the existing battery preparation process that needs to be wound, the diaphragm in the embodiments of this application has a larger thickness, no winding process, and a simple setting method, which can solve the problems of wavy edges of the diaphragm, uneven tension and edge collapse, and wrinkling of the diaphragm in the existing process.

[0064] The conductive member includes a positive electrode conductive member 6 and a negative electrode conductive member 7. At least part of the positive electrode conductive member 6 and the negative electrode conductive member 7 extends along the height direction of the housing 1, and at least part of the positive electrode conductive member 6 and the negative electrode conductive member 7 are respectively arranged in the positive electrode trough 4 and the negative electrode trough 5 to achieve conductive current collection.

[0065] In some embodiments, the positive electrode conductive member 6 and the negative electrode conductive member 7 are made of a metal material. The shape of the metal material can be strip-shaped, column-shaped, sheet-shaped, regular-shaped or irregular-shaped. Both the positive electrode conductive member 6 and the negative electrode conductive member 7 can be formed by connecting one or more than two metal materials.

[0066] As Figure 2 shown, in this embodiment, the positive electrode conductive member 6 includes a positive electrode conductive current collection net arranged in a grid pattern. The positive electrode conductive current collection net is formed by a plurality of aluminum wires arranged along the length direction and the width direction of the housing 1 and having intersections, and the intersections of the aluminum wires are connected by welding. The aluminum wire can be formed by an aluminum alloy through a drawing process, which has low processing difficulty and can avoid problems in the existing process of rolled aluminum foil, such as difficult removal of lubricating rolling oil resulting in the inability of the coating material to adhere, easy breakage of the strip during rolling processing, and low yield.

[0067] The negative electrode conductive member 7 includes a negative electrode conductive busbar network arranged in a grid pattern. The negative electrode conductive busbar network is formed by a plurality of copper wires arranged along the length and width directions of the housing 1 and having intersections. The intersections of the copper wires are connected by welding. The copper wires can be formed by drawing electrolytic copper material with a purity of greater than or equal to 99.99% copper. The processing difficulty is low, and it can avoid the problems existing in the rolled copper foil in the existing process, including brittle fracture caused by acid mist corrosion during the processing of electrolytic copper foil, uneven tension and edge collapse, and poor thickness consistency. Moreover, special surface treatment is required to prevent oxidation with water during the coating process, and the processing process is complex, etc.

[0068] It can be understood that due to the setting of the separator 3, the intersections where multiple aluminum wires intersect and the intersections where multiple copper wires intersect are both higher than the highest point of the separator 3.

[0069] Such as Figure 3 and Figure 4 As shown, in this embodiment, the top intersection 601 of the positive electrode conductive member 6 is higher than the top intersection 701 of the negative electrode conductive member 7.

[0070] Since the distance between the positive electrode conductive member 6 and the negative electrode conductive member 7 is relatively close, an insulating plate 12 is provided between the top intersection 601 of the positive electrode conductive member 6 and the top intersection 701 of the negative electrode conductive member 7 to isolate the positive electrode conductive member 6 and the negative electrode conductive member 7, thereby preventing short - circuit between the positive and negative electrodes of the lithium battery. The insulating plate 12 is provided with through - holes 13 for the aluminum wires to pass through.

[0071] In this embodiment, the busbar plate 8 is arranged above the top intersection 601 of the positive electrode conductive member 6. A plurality of busbar pieces are spaced apart on the side of the busbar plate 8 facing away from the insulating plate 12. The busbar pieces are made of metal material. In this embodiment, the busbar pieces are selected as busbar aluminum pieces. The busbar pieces are used to connect with the conductive busbar network and the battery terminal posts to achieve conductive current collection. The busbar plate 8 is made of insulating material.

[0072] The busbar pieces include a positive electrode busbar piece 9 and a negative electrode busbar piece 10. The positive electrode busbar piece 9 and the negative electrode busbar piece 10 are respectively connected to the positive electrode conductive member 6 and the negative electrode conductive member 7.

[0073] Specifically, as Figure 2 、 Figure 4 and Figure 5 As shown, in this embodiment, the busbar plate 8 is provided with through - holes for the aluminum wires and copper wires to pass through. After the positive electrode conductive member 6 converges, part of the aluminum wires pass through the busbar plate 8 and protrude from the upper surface of the busbar plate 8. After the negative electrode conductive member 7 converges, part of the copper wires pass through the busbar plate 8 and protrude from the upper surface of the busbar plate 8, and are respectively connected to the positive electrode busbar piece 9 and the negative electrode busbar piece 10 located on the upper surface of the busbar plate 8 to achieve conductive current collection. Among them, the upper surface of the busbar plate 8 is the surface of the busbar plate 8 facing away from the insulating plate 12.

[0074] As Figure 2 shown, the bus bar 8 is provided with vent holes 11 in its thickness direction, and the vent holes 11 are used for gas circulation during the formation process.

[0075] The cover plate 14 is arranged at the opening of the housing 1 to close the opening, as Figure 6 and Figure 9 shown. The cover plate 14 is provided with a pole hole and an explosion-proof hole 19. A pole is provided in the pole hole, and the pole is connected to the bus bar through a connecting piece to achieve electrical conduction.

[0076] Optionally, the cover plate 14 is made of a material resistant to hydrofluoric acid and is integrally formed by injection molding. In some embodiments, the cover plate 14 can be made of polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), or other materials. In the embodiments of the present application, the cover plate 14 fixes the pole by injection molding, and the pole protrudes from both side surfaces of the cover plate 14. Compared with the existing metal cover plate, the present application can reduce the conductive sealing ring provided on the cover plate, the insulating sealing ring connecting the negative pole and the cover plate, and the lower plastic for fixing the cover plate and the pole, can reduce the processes and materials, reduce the process difficulty, and reduce the production cost.

[0077] Specifically, the pole includes a positive pole 15 and a negative pole 16. Both the positive pole 15 and the negative pole 16 penetrate through both side surfaces of the cover plate 14. The connecting piece includes a positive connecting piece 15 and a negative connecting piece 16. One ends of the positive connecting piece 15 and the negative connecting piece 16 are respectively connected to the positive pole 15 and the negative pole 16, and the other ends are respectively connected to the positive bus bar 9 and the negative bus bar 10.

[0078] Optionally, the positive pole 15, the negative pole 16, the positive connecting piece 15, and the negative connecting piece 16 are all made of aluminum alloy material and are connected by welding. Compared with the existing method of using friction welding between copper and aluminum alloy for the negative pole to splice and connect with the ear and the connecting piece, the pole and the connecting piece in the embodiments of the present application can reduce the cost and the connection method is simpler.

[0079] As Figure 7 and Figure 8 shown, a detachable explosion-proof valve 20 is provided in the explosion-proof hole 19. In this embodiment, an internal thread 23 is provided in the explosion-proof hole 19, an external thread 24 is provided on the explosion-proof valve 20, and the explosion-proof valve 20 is spirally connected to the explosion-proof hole 19 through the internal thread 23 and the external thread 24.

[0080] In this embodiment, a second sealing ring 22 is provided on the outer peripheral side of the explosion-proof hole 19 to seal the explosion-proof hole 19.

[0081] A through hole is provided in the explosion-proof valve 20, and an explosion-proof film 25 is provided in the through hole. Scratches 26 are provided on the surface of the explosion-proof film 25.

[0082] Optionally, both the explosion-proof valve 20 and the explosion-proof film 25 are made of metal materials. In a possible embodiment, both the explosion-proof valve 20 and the explosion-proof film 25 are made of aluminum alloy. The installation method of the explosion-proof valve 20 in the embodiment of the present application is simple, and the explosion-proof valve 20 can be repeatedly disassembled through the detachable explosion-proof valve 20, so as to inject liquid or carry out formation through the explosion-proof hole 19.

[0083] The embodiment of the present application also provides a lithium battery manufacturing method, including the following steps:

[0084] S1, Prepare the housing 1, and set the separator 3 in the housing 1 to form a positive electrode groove 4 and a negative electrode groove 5.

[0085] S2, Prepare the conductive members. The conductive members include a positive electrode conductive member 6 and a negative electrode conductive member 7. At least part of the negative electrode conductive member 7 is sequentially arranged in the negative electrode groove 5, an insulating plate 12 is arranged above the top end of the negative electrode conductive member 7, and at least part of the positive electrode conductive member 6 is arranged in the positive electrode groove 4 through the through hole 13 of the insulating plate 12.

[0086] In this embodiment, both the positive electrode conductive member 6 and the negative electrode conductive member 7 are conductive busbar meshes arranged in a grid pattern. Among them, since the negative electrode conductive busbar mesh is placed below the insulating plate 12, between the top end of the separator 3 and the insulating plate 7, the negative electrode conductive busbar mesh can be provided with multiple intersections at different heights.

[0087] The positive electrode conductive busbar mesh passes a plurality of aluminum wires through the through holes 13 on the insulating plate 12. The intersections of the aluminum wires in the positive electrode conductive busbar mesh are located between the insulating plate 12 and the busbar plate 8, and the intersections of the positive electrode conductive busbar mesh are all located above the insulating plate 12.

[0088] S3, Prepare the electrode materials. The electrode materials include a positive electrode material and a negative electrode material, and the positive electrode material and the negative electrode material are respectively poured into the positive electrode groove 4 and the negative electrode groove 5.

[0089] Among them, the materials include active materials, conductive agents, binders and solvents, and the solvent is an electrolyte solution.

[0090] This step further includes:

[0091] Dividing the electrolyte solution into a first electrolyte solution and a second electrolyte solution according to a preset portion, and the sum of the portions of the first electrolyte solution and the second electrolyte solution is equal to the portion of the electrolyte solution;

[0092] Adding the first electrolyte solution to the mixture of the active material, the conductive agent and the binder, and stirring at a preset temperature to make it fully mixed, so as to obtain a first mixture;

[0093] Adding the second electrolyte solution to the first mixture, and stirring at a preset temperature to make it fully mixed, so as to obtain the electrode material;

[0094] Pour the electrode material into the housing and expel the gas mixed in the electrode material.

[0095] In a possible embodiment, during the process of pouring the electrode material, the housing 1 is vibrated by ultrasonic waves to vibrate the electrode material, thereby expelling the gas mixed in the electrode material.

[0096] Specifically, a double planetary vacuum mixer and a dry kneading process are used to prepare the electrode material. During stirring, the temperature is less than or equal to 30°C, and the circulating water temperature for cooling the material in the mixer is less than or equal to -5°C to prevent the electrolyte from decomposing at high temperatures. The preparation steps and the solid content during the preparation of the positive electrode material and the negative electrode material are the same, and the solid content is set at 70% - 85% of the total amount of the electrode material. The solid content is the proportion of the solid component in the total weight of the material.

[0097] In the embodiment of the present application, the N-methylpyrrolidone (NMP) solvent during the production of the existing positive electrode material and the ultrapure water during the production of the negative electrode material are used as the electrolyte. By directly wetting the active material, conductive agent, and binder with the electrolyte, it is possible to save the equipment investment and recycling energy consumption of N-methylpyrrolidone (NMP) materials and ultrapure water, reduce the primary liquid injection process, save the equipment investment and processing energy consumption cost of the liquid injection process, avoid the problem of difficult liquid injection infiltration, and improve the battery cycle life performance.

[0098] S4. Prepare the bus bar 8, and connect the positive electrode conductive member 6 and the negative electrode conductive member 7 to the bus bar pieces on the bus bar 8 respectively.

[0099] S5. Prepare the cover plate 14. After connecting the cover plate 14 to the bus bar 8, connect the cover plate 14 to the housing 1.

[0100] Specifically, the bus bar 8 is arranged above the top intersection 601 of the positive electrode conductive bus bar network. The aluminum wire and the copper wire are respectively passed through the through holes on the bus bar 8, and the aluminum wire and the copper wire are respectively connected to the positive electrode bus bar piece 9 and the negative electrode bus bar piece 10 by welding. After the positive electrode bus bar piece 9 and the negative electrode bus bar piece 10 are respectively welded and connected to the positive electrode terminal 15 and the negative electrode terminal 16 through the positive electrode connecting piece 15 and the negative electrode connecting piece 16, the cover plate 14 is connected to the opening of the housing 1, so that the positive electrode connecting piece 15 and the negative electrode connecting piece 16 completely cover the inside of the cover plate 14 and the housing 1. The contact ends of the cover plate 14 and the housing 1 are fused by pressure ultrasonic welding to form a sealed battery. This step can reduce the laser welding of the tab and the connecting piece during the production of the existing cover plate, reduce the welding difficulty, and since the connecting piece, terminal, and bus bar piece are all made of aluminum alloy, it is possible to reduce the laser welding power, save energy consumption, and reduce equipment investment.

[0101] S6. Perform process treatment on the battery after connecting the cover plate 14 to obtain the target lithium battery.

[0102] The process treatment includes:

[0103] Formation: Charge and discharge the battery. Through high-temperature and negative-pressure formation, specifically, remove the explosion-proof valve, and use a vacuum negative-pressure pipeline to connect to the explosion-proof hole to extract the gas generated during formation.

[0104] Liquid injection: The liquid injection is to supplement the electrolyte inside the battery. When injecting the liquid, remove the explosion-proof valve and inject the electrolyte through the explosion-proof hole.

[0105] Capacity grading: The process of screening out batteries with the same capacity through charge and discharge tests to ensure the consistency of battery capacity. Keep the temperature constant at room temperature during capacity grading.

[0106] K value measurement: Measure the self-discharge rate of the battery. Specifically, evaluate the self-discharge performance of the battery by measuring the voltage drop of the battery within a specific time interval. Usually, choose to measure the pressure at room temperature or high temperature after standing.

[0107] Sorting: The process of classifying batteries according to specific quality parameters. The quality parameters include capacity, voltage, internal resistance, etc.

[0108] In the present invention, specific embodiments are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A lithium battery, characterized in that, Comprising: A housing having an opening, within which there are a positive electrode chamber and a negative electrode chamber separated by a separator. When viewed in the arrangement direction of the positive electrode chamber and the negative electrode chamber, the cross-sectional area of the negative electrode chamber is larger than that of the positive electrode chamber. Positive electrode material and negative electrode material are respectively provided in the positive electrode chamber and the negative electrode chamber; A conductive member including a positive electrode conductive member and a negative electrode conductive member. At least part of the positive electrode conductive member and the negative electrode conductive member extend along the height direction of the housing and are respectively provided in the positive electrode chamber and the negative electrode chamber; A bus bar on which bus bar tabs are spaced, and the bus bar tabs are respectively connected to the positive electrode conductive member and the negative electrode conductive member; A cover plate provided at the opening and respectively connected to the housing and the bus bar tabs, enclosing the conductive member and the bus bar between the housing and the cover plate.

2. A lithium battery according to claim 1, wherein Protrusions are provided on the inner surface of the housing, and the separator is connected to the protrusions, so that the separator and the protrusions enclose to form the positive electrode chamber, and the separator and the housing enclose to form the negative electrode chamber.

3. A lithium battery according to claim 1, wherein, A groove is provided on the peripheral side of the opening of the housing, and a first sealing ring is provided in the groove.

4. A lithium battery according to claim 1, characterized in that, The positive electrode conductive member includes a positive electrode conductive bus bar network arranged in a grid pattern, which is formed by a plurality of aluminum wires arranged along the length direction and the width direction of the housing and having intersections. The negative electrode conductive member includes a negative electrode conductive bus bar network arranged in a grid pattern, which is formed by a plurality of copper wires arranged along the length direction and the width direction of the housing and having intersections.

5. A lithium battery according to claim 4, characterized in that, The intersections of the positive electrode conductive bus bar network are higher than the intersections of the negative electrode conductive bus bar network. An insulating plate is provided between the intersections of the positive electrode conductive bus bar network and the top intersections of the negative electrode conductive bus bar network, and through holes for the aluminum wires to pass through are provided on the insulating plate.

6. A lithium battery according to claim 1, characterized in that, The thickness of the separator is less than or equal to 0.3 mm, and at least one through hole is provided on the separator.

7. A lithium battery according to claim 1, characterized in that, Vent holes are provided on the bus bar.

8. A lithium battery according to claim 1, characterized in that, Pole columns and explosion-proof holes are provided on the cover plate. Connection tabs are provided on the pole columns, and the connection tabs are connected to the bus bar tabs. A detachable explosion-proof valve is provided in the explosion-proof holes, and a second sealing ring is provided outside the explosion-proof holes.

9. A method for manufacturing a lithium battery, characterized in that, Including the following steps: Preparing a housing, and arranging a separator in the housing to form a positive electrode chamber and a negative electrode chamber; Preparing a conductive member, which includes a positive electrode conductive member and a negative electrode conductive member. In sequence, at least part of the negative electrode conductive member is arranged in the negative electrode chamber, an insulating plate is arranged at the top of the negative electrode conductive member, and at least part of the positive electrode conductive member is arranged in the positive electrode chamber through the insulating plate; Preparing electrode materials, which include positive electrode material and negative electrode material, and pouring the positive electrode material and the negative electrode material into the positive electrode chamber and the negative electrode chamber respectively; Preparing a bus bar, and connecting the positive electrode conductive member and the negative electrode conductive member to the bus bar tabs on the bus bar respectively; Preparing a cover plate, after connecting the cover plate to the bus bar, connecting the cover plate to the housing; Performing a process treatment on the battery after connecting the cover plate to obtain a target lithium battery.

10. A method for manufacturing a lithium battery according to claim 9, characterized in that, The electrode material includes an active material, a conductive agent, a binder and a solvent, and the solvent is an electrolyte. The steps for preparing the electrode material include: Dividing the electrolyte into a first electrolyte and a second electrolyte according to a preset amount, and the sum of the amounts of the first electrolyte and the second electrolyte is equal to the amount of the electrolyte; Adding the first electrolyte to the mixture of the active material, the conductive agent and the binder, and stirring at a preset temperature to fully mix them, so as to obtain a first mixture; Adding the second electrolyte to the first mixture, and stirring at a preset temperature to fully mix them, so as to obtain the electrode material; Pouring the electrode material into the shell and removing the gas mixed in the electrode material.

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