Large-capacity battery manufacturing method and large-capacity battery

Abstract

This application discloses a method for manufacturing a large-capacity battery and a large-capacity battery, and mainly aims to solve the problems of poor consistency, unstable performance, and poor overall performance of existing large-capacity lithium batteries. This method includes the steps of assembling wound cells or stacked cells that constitute a large-capacity battery core separately to prepare a battery core, and then performing chemical formation and capacity grading, and grouping each battery core according to one or more of capacity, internal resistance, voltage, and self-discharge, connecting the battery cores in the same group in parallel and placing them in a large-capacity battery box, and then performing a second injection, sealing, and capacity grading. According to this application, after one injection, the battery can be formed, capacity graded, and classified, and multiple batteries of the same grade can be connected in parallel and placed in a large-capacity battery box before being re-injected, improving the consistency of each parallel-connected cell of the large-capacity battery, as well as improving the quality control efficiency and battery quality of the large-capacity battery.

Description

[Technical Field]

[0001] The present application belongs to the technical field of lithium batteries, and specifically relates to a method for manufacturing a large-capacity battery and a large-capacity battery. [Background technology]

[0002] Typically, the maximum capacity of commercially available prismatic lithium iron phosphate batteries is 400Ah, while the maximum capacity of cylindrical batteries is no more than 100Ah. However, with the rise of new energy vehicles and new energy public transportation vehicles, the demand for lithium-ion battery capacity is increasing. Therefore, when manufacturing high-capacity lithium batteries, multiple cores must be connected in parallel. This often leads to problems with high-capacity batteries, such as battery overheating, overcharging, and poor consistency during use. Furthermore, when multiple cores are connected in parallel, variations in performance parameters such as core capacity, resistance, voltage, and self-discharge often occur. A quality problem with one core can affect the performance of the entire high-capacity battery. This leads to poor consistency after the cores are connected in parallel, resulting in unstable performance and high waste rates. Furthermore, most existing high-capacity lithium batteries are manufactured by connecting multiple cores in parallel and then uniformly injecting electrolyte, which results in poor overall performance. Summary of the Invention

[0003] In this application, a method for manufacturing a large-capacity battery and a large-capacity battery are proposed in response to the problems of existing large-capacity lithium batteries, such as difficult quality control, poor consistency, unstable performance, and high waste rates.

[0004] According to the method of the present application, after one injection, the batteries are subjected to chemical formation, capacity grading, and classification, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box before being re-injected with electrolyte. This improves the consistency of each parallel-connected cell in the large-capacity battery, thereby improving the efficiency of quality control and battery quality of the large-capacity battery.

[0005] The specific technical proposal of the present application is as follows:

[0006] A method for manufacturing a large-capacity battery, comprising the steps of assembling wound cells or laminated cells that constitute a large-capacity battery core to form a battery core, and then performing chemical formation and capacity grading; and grouping the battery cores according to one or more of capacity, internal resistance, voltage, and self-discharge, connecting the battery cores in the same group in parallel and placing them in a large-capacity battery box, performing secondary liquid injection so that the electrolyte in the battery core and the electrolyte in the large-capacity battery box can mutually pass through each other, followed by sealing and capacity grading.

[0007] Furthermore, the wound or stacked cell of the large-capacity battery core includes at least one wound or stacked core.

[0008] Furthermore, the battery cores manufactured using the at least one wound core or laminated core are classified according to one or more of capacity, internal resistance, voltage, and self-discharge, specifically into Class A, Class B, and Class C.

[0009] Furthermore, discard the C-class batteries, combine at least one A-class battery with one A-class battery, combine B-class battery with one B-class battery, remove the battery core packaging, and place the combined battery cores into a large-capacity battery box.

[0010] Furthermore, the assembled battery cores are placed in a large-capacity battery box, and then a secondary injection is performed. After the secondary injection, the injection holes of the large-capacity batteries are sealed, and after sealing, the large-capacity batteries are assigned a capacity rating.

[0011] Furthermore, the large-capacity battery core includes a core shell, which is made of a plastic material, and has a protruding conduit disposed therein.

[0012] Furthermore, the large-capacity battery core further comprises a core body, the core shell is coated on the outside of the core body, and the conduit communicates with the electrolyte chamber of the core body.

[0013] Furthermore, the plastic material has a melting point of more than 130°C and is one or a combination of two or more selected from polyformaldehyde, polyvinyl chloride, polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate and polyester resin.

[0014] Furthermore, the conduit has a sealed distal opening, a weak groove disposed in the outer wall, and a tension ring at the distal end.

[0015] Furthermore, the conduit is a liquid infusion tube.

[0016] Furthermore, connecting battery cores in the same group in parallel specifically includes placing the plurality of battery cores on a pressure bracket, stacking the plurality of battery cores sequentially from bottom to top in the electrolyte chamber of the large-capacity battery box, and connecting the plurality of large-capacity battery cores in parallel using a parallel connection bus bar.

[0017] Furthermore, placing the parallel-connected large-capacity battery cores in a large-capacity battery box and then performing secondary filling, sealing, aging, and capacity grading specifically includes placing the parallel-connected large-capacity battery cores in the electrolyte chamber of the large-capacity battery box and then opening the conduits in each of the large-capacity battery cores, or opening the conduits in each of the large-capacity battery cores and then placing the large-capacity battery cores in the electrolyte chamber of the large-capacity battery box, connecting the electrolyte chambers of the large-capacity battery cores to the electrolyte chamber of the large-capacity battery box, vacuum-extracting the electrolyte chamber of the large-capacity battery box, filling the electrolyte chamber of the large-capacity battery box with electrolyte, and attaching a pressure release component to the filling port of the large-capacity battery box after the filling is completed.

[0018] Furthermore, the method for opening the conduit is as follows: a conduit pulling wire is wound around the pulling ring of each of the large-capacity battery cores, and the conduit is broken along the weak groove by pulling the conduit pulling wire, thereby opening the conduit.

[0019] At the same time, the present application proposes a large-capacity battery, which is manufactured by the above-mentioned method for manufacturing a large-capacity battery.

[0020] Compared with existing technologies, the present invention can provide the following beneficial effects:

[0021] 1. The method for manufacturing a large-capacity battery according to the present application includes the steps of assembling wound or stacked cells that make up the large-capacity battery core to form a battery core, then performing chemical formation and capacity grading, and grouping the battery cores according to one or more of capacity, internal resistance, voltage, and self-discharge, connecting the battery cores in the same group in parallel and placing them in a large-capacity battery box, allowing the electrolyte in the battery cores to pass through the electrolyte in the large-capacity battery box, and then sealing and capacity grading. According to the method of the present application, after a single injection, the batteries are subjected to chemical formation, capacity grading, and classification, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box before being re-injected, thereby improving the consistency of each parallel-connected cell in a large-capacity battery and, in addition, improving the efficiency of quality control and battery quality of large-capacity batteries.

[0022] 2. In the manufacturing method of the present application for a large-capacity battery, the manufactured large-capacity battery cores are subjected to chemical formation and capacity grading, and then classified based on the results of the capacity grading. Large-capacity battery cores of the same grade are then placed in the electrolyte compartment of the same large-capacity battery box, thereby avoiding the problem of variations in performance parameters such as capacity, resistance, voltage, and self-discharge of cores in the same large-capacity battery box and improving the consistency of the large-capacity battery cores after parallel connection.

[0023] 3. The large-capacity battery core according to the present invention comprises a core shell, which is made of plastic material; the use of plastic material significantly reduces the manufacturing cost of lithium batteries while maintaining the same product quality as existing products. The core shell is provided with a protruding conduit, which allows the electrolyte chamber of the core shell to communicate with the outside.

[0024] 4. The large-capacity battery core according to the method of the present application comprises a core body, a core shell covering the outside of the core body, and a conduit communicating with the electrolyte chamber of the core body; the end opening of the conduit is sealed, and a weak groove is disposed on the outer wall surface of the conduit; and a tension ring is disposed at the end of the conduit; during use, the tension ring can be used to break the conduit from the weak groove, allowing the electrolyte chamber of the core body in the core shell to communicate with the outside.

[0025] 5. According to the method of the present application, the electrolyte chambers of the multiple large-capacity battery cores are connected to the electrolyte chamber of the large-capacity battery box via conduits, so that the electrolyte chambers of the large-capacity battery cores and the electrolyte chamber of the large-capacity battery box share the same electrolyte, further improving the performance of the large-capacity lithium battery; at the same time, if one of the large-capacity battery cores is damaged, the other multiple large-capacity battery cores can still be connected by the parallel connection busbar and continue to function normally.

[0026] 6. The large-capacity battery according to the method of the present application further includes a pressure bracket placed in the electrolyte chamber of the large-capacity battery box. The pressure bracket improves the stability of the placement of the large-capacity battery cores and prevents misalignment of multiple large-capacity battery cores. In addition, it effectively prevents damage to the large-capacity battery caused by improper connection and alignment during the parallel connection of the cores. The parallel-connected large-capacity battery of the present application can significantly improve the quality consistency and yield of large-capacity batteries.

[0027] 7. In the large-capacity battery according to the method of the present application, a pressure release port is provided on the combined top cover above the large-capacity battery box, and a pressure release component is attached to the pressure release port. The pressure release component communicates with the electrolyte chamber of the large-capacity battery box, and electrolyte can also be injected through the pressure release port. In other words, the pressure release port can be used as an injection hole, and after injection is complete, the pressure release component is attached to the pressure release port. The pressure release component makes it easy to exhaust gas and release pressure if gas is generated due to thermal runaway in the large-capacity battery.

[0028] Additional advantages, goals, and features of the present application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art through study and practice of the present application. [Brief explanation of the drawings]

[0029] In order to more clearly explain the embodiments of the present application or the technical solutions of the existing technology, the following will briefly describe the drawings necessary for explaining the embodiments or the existing technology. Needless to say, the drawings mentioned in the following description only relate to some of the embodiments of the present application, and those skilled in the art can obtain other drawings from these drawings without any creative work.

[0030] [Figure 1] 1 is a schematic diagram of a method for manufacturing a large-capacity battery according to the present application. [Figure 2] 1 is a schematic diagram 1 of the configuration of a large-capacity core body in a method according to Example 2 of the present application. [Figure 3] 2 is a schematic diagram 2 of the configuration of a large-capacity battery core in a method according to Example 2 of the present application. [Figure 4] 3 is a schematic diagram 3 of the configuration of a large-capacity battery core in a method according to Example 2 of the present application. [Figure 5] FIG. 10 is a schematic diagram of the connection between the pressure bracket and the battery core in the method according to the second embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram of a parallel connection bus bar connection in a method according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram illustrating the configuration of a parallel-connected large-capacity battery in a method according to Example 2 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present application will be described in detail below in conjunction with the drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely for interpreting the technical principles of the present application and are not intended to limit the scope of protection of the present application.

[0032] For large-capacity batteries, the consistency of the resistance, capacity, voltage, and self-discharge of each wound or laminated core connected in parallel inside the battery is a key indicator, and using wound or laminated cores with poor consistency can lead to various defects such as battery capacity not reaching the standard, battery overheating and overcharging, poor consistency, etc. Based on this, this application proposes a method for manufacturing a large-capacity battery.

[0033] FIG. 1 shows a schematic flow chart of a method for manufacturing a large-capacity battery according to the present invention, which includes the following steps 101 to 103.

[0034] Step 101: Assemble the wound cells or laminated cells that make up the large-capacity battery core individually to form a battery core, and then perform chemical formation and capacity grading. Capacity grading is the detection and calibration of the capacity, internal resistance, voltage, and self-discharge of the battery core or large-capacity battery.

[0035] Step 102: Each battery core is divided into groups according to one or more of capacity, internal resistance, voltage, and self-discharge, and the battery cores in the same group are combined, connected in parallel, and placed in a large-capacity battery box.

[0036] Step 103: A secondary injection is carried out so that the electrolyte in the battery core and the electrolyte in the large-capacity battery box can pass through each other, and then sealing and capacity grading are carried out.

[0037] The wound or laminated cell of the above-mentioned large-capacity battery core includes at least one wound or laminated core. First, at least one wound or laminated core is assembled to form a battery core, which is then chemically formed and capacity graded. The battery cores made from at least one wound or laminated core are classified according to one or more of capacity, internal resistance, voltage, and self-discharge. The battery cores made from at least one wound or laminated core are then classified into grade A, B, C, or higher according to the above grades. The grade C cores are discarded, and at least one grade A is combined with another grade A, and one grade B is combined with another grade B. The battery cores are then unwrapped and placed in a large-capacity battery box. After being placed in the large-capacity battery box, secondary injection is performed. After the secondary injection, the injection holes of the large-capacity battery are sealed, and the large-capacity battery is then capacity graded.

[0038] Before the secondary injection, the battery core must be opened (i.e., the battery core is unsealed) so that the inner chamber of the battery core and the inner chamber of the large-capacity battery box are in communication with each other. After the secondary injection, the electrolyte in the battery core and the electrolyte in the large-capacity battery box can pass through each other. Alternatively, the shell of the battery core is provided with a dissolvable sheet that is soluble in the electrolyte. This dissolvable sheet is formed during the manufacture of the battery core. After the secondary injection, the dissolvable sheet is dissolved by the electrolyte in the battery box, allowing the electrolyte in the battery core and the electrolyte in the large-capacity battery box to pass through each other. Specifically, the dissolvable sheet is made of a material that is soluble in the electrolyte, such as polymethyl methacrylate, polyvinyl chloride, polycarbonate, or ABS plastic. To prevent the dissolvable sheet from dissolving in the electrolyte in the battery core before the secondary injection, an isolating film may be provided on one side of the dissolvable sheet facing the inside of the battery core. Although the isolating film is insoluble in the electrolyte, it can fall off after the dissolvable sheet dissolves, allowing the electrolyte in the battery core and the electrolyte in the large-capacity battery box to pass through each other.

[0039] Example 1 For a 1000Ah large-capacity battery, ten groups of 100Ah laminated cores are used. First, the positive and negative electrode materials are prepared, coated, compacted, and cut, and then laminated to form a laminated core. The positive and negative electrodes are welded to the laminated core, placed in a simple soft pack, injected with electrolyte, vacuum extracted, and then formed and capacity graded. The internal resistance is graded according to 0.5mΩ≦R<0.55mΩ, 0.55mΩ≦R≦0.6mΩ, and R>0.6mΩ, and the batteries are graded into three categories: A, B, and C. C The battery is then reclassified according to the resistance range, voltage difference within the group≦10mV, and capacity difference within the group≦2Ah. The batteries in the same group are connected in parallel using poles, the soft packs are removed and compressed, and the batteries are placed in a large-capacity battery box with a combination top cover attached. They are then vacuum extracted, injected, and sealed again to form a consistent 1000Ah large-capacity battery. The large-capacity battery can then be capacity-graded, and aged at high temperature before capacity grading.

[0040] In the manufacturing method for a large-capacity battery according to this embodiment, the wound cells or laminated cells that make up the large-capacity battery core are individually assembled to form a battery core, and then chemical formation and capacity grading are performed. The cells are then divided into groups that are similar to each other according to one or more of capacity, internal resistance, voltage, and self-discharge, and the cells are combined within the groups, connected in parallel, and placed in a large-capacity battery box. Further, a secondary liquid injection is performed so that the electrolyte in the battery core and the electrolyte in the large-capacity battery box can mutually pass through each other, and then the cells are sealed and capacity grading is performed.

[0041] According to the method of this embodiment, after one injection, the batteries are subjected to chemical formation, capacity grading, and classification, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box before being re-injected with electrolyte. This improves the consistency of each parallel-connected cell in the large-capacity battery, and improves the quality control efficiency and battery quality of the large-capacity battery.

[0042] This embodiment further proposes a large-capacity battery manufactured using the chemical formation and capacity grading process for large-capacity batteries described in the above embodiment. According to the large-capacity battery of this embodiment, after one injection, the batteries are subjected to chemical formation, capacity grading, and classification, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box before being re-injected with electrolyte, thereby improving the consistency of each parallel-connected cell in the large-capacity battery and improving the efficiency of quality control and battery quality of the large-capacity battery.

[0043] Example 2 The method for assembling the parallel-connected large-capacity battery according to this embodiment includes the following steps.

[0044] 1) A mounting groove is press-formed at the center of one side of the core shell 5, the core connected to the conductive connection sheet 2 and the tab current collecting sheet 3 is placed in the mounting groove, and the other side of the core shell 5 is crimped to form an electrolyte chamber of the core body 1 inside the core shell 5, and during the crimping process, three sides of the core shell 5 are first crimped to seal the three sides of the core shell 5, and the other side is opened, and electrolyte is injected into the electrolyte chamber of the core body 1 through the opening, and after the electrolyte injection is completed, the open side is sealed; or, during the crimping process, four sides are crimped, and electrolyte is injected into the electrolyte chamber of the core body 1 through the conduit 4, and after the injection is completed, the conduit 4 is sealed, and the conduit 4 communicates with the electrolyte chamber of the core body 1, and in this way the core is formed.

[0045] The cores are assigned a capacity rating, and after the capacity rating is completed, they are classified according to the capacity range, internal resistance range, self-discharge range, and voltage range. In this embodiment, batteries with a capacity range of 40 to 40.5 Ah, an internal resistance range of 0.9 to 1 mΩ, a self-discharge range of 2% per month or less, and a voltage range of 3.2 ± 0.1 V are classified as Class A. Battery batteries with a capacity range of 39.5 to 40 Ah, an internal resistance range of 1 to 1.1 mΩ, a self-discharge range of 2% to 4% per month, and a voltage range of 3.2 ± 0.01 V are classified as Class B. Battery batteries with a capacity range of 39.5 Ah or less or 40.5 Ah or more, an internal resistance range of 0.9 mΩ or less or 1.1 mΩ or more, a self-discharge range of 4% or more per month, and a voltage range other than 3.2 ± 0.01 V are classified as Class C.

[0046] 25 large-capacity battery cores of the same grade are sequentially placed in the mounting tank of the pressure bracket 7, the positive electrode tab current collecting sheets of the 25 large-capacity battery cores are connected in parallel to one parallel connection bus bar 8, the negative electrode tab current collecting sheets of the 25 large-capacity battery cores are connected in parallel to another parallel connection bus bar 8, the upper lid 13 is attached to the top lid of the large-capacity battery box 10, the parallel connection bus bar 8 connected to the positive electrode tab current collecting sheet is connected to the positive electrode pole, and the parallel connection bus bar 8 connected to the negative electrode tab current collecting sheet is connected to the negative electrode pole, thus forming a parallel-connected large-capacity battery.

[0047] The parallel-connected large-capacity batteries are placed in the electrolyte chamber of the large-capacity battery box 10, and a conduit tension wire 9 is wound around the tension ring 42 of the conduit 4 of each of the large-capacity battery cores; the assembly top cover 13 is attached to the top of the large-capacity battery box 10, and the conduit tension wire 9 is passed through the pressure release port 14 of the assembly top cover 13 and pulled to break the conduit 4 from the weak groove 41 and release the conduit 4; or the conduit tension wire 9 is wound around the tension ring 42 of the conduit 4 of each of the large-capacity battery cores and pulled to break the conduit 4 from the weak groove 41 and release the conduit, and then the parallel-connected large-capacity batteries are placed in the electrolyte chamber of the large-capacity battery box 10; in this way, the electrolyte chamber of each of the large-capacity battery cores is connected to the electrolyte chamber of the battery box 10 via the conduit 4.

[0048] The pressure release port 14 is used to evacuate the electrolyte chamber of the large-capacity battery box 10, and the injection valve is used to inject electrolyte into the electrolyte chamber of the large-capacity battery box 10, thereby forming a shared electrolyte system between each of the large-capacity battery cores and the large-capacity battery box 10; after the injection is completed, a pressure release valve 11 or an explosion-proof membrane is attached to the pressure release port 14.

[0049] As shown in Figures 2 and 3, the large-capacity battery core according to this embodiment comprises a core shell 5 and a core body 1, the core shell 5 is made of a plastic material, a protruding conduit 4 is disposed on the core shell 5, the core shell 5 is covered on the outside of the core body 1, and the conduit 4 is in communication with the electrolyte chamber of the core body 1.

[0050] It is particularly noted that the plastic material in this embodiment is one or a combination of two or more selected from polyformaldehyde, polyvinyl chloride, polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyester resins, and preferably, the plastic material in this embodiment is polypropylene.

[0051] According to this embodiment, a core body 1 has two opposing tab current collecting sheets 3 connected to it, one of which has a positive electrode tab current collecting sheet connected to it and the other has a negative electrode tab current collecting sheet connected to it. In use, a mounting groove is pressed into one side of the core shell 5, the core body 1 is placed in the mounting groove, and the other side of the core shell 5 is crimped. The core shell 5 is then placed on the outside of the core body 1 to seal it, and an electrolyte chamber for the core body 1 is formed inside the core shell 5. During the crimping process, three sides are first crimped to seal the three sides, and the other side is opened. Electrolyte is injected into the electrolyte chamber of the core body 1 through the opening, and the opening is sealed after the electrolyte injection is complete; alternatively, four sides are crimped during the crimping process, and electrolyte is injected into the electrolyte chamber of the core body 1 through the conduit 4, and after the injection is complete, the conduit 4 is sealed, and the conduit 4 communicates with the electrolyte chamber of the core body 1, and the tab current collecting sheet 3 extends to the outside of the core shell 5.

[0052] It is particularly noted that in this embodiment, a ring-shaped weak groove 41 is provided on the outer wall surface of the conduit 4, and a tension ring 42 is provided at the end opening of the conduit 4. As shown in Figure 4, in this embodiment, if the conduit 4 does not have the weak groove 41 and the tension ring 42, the end of the conduit 4 can be directly sealed with the sealing cap 6; if the conduit needs to be broken, it can be broken from the connection point of the conduit 4 with the sealing cap 6.

[0053] Preferably, the battery core according to this embodiment is a wound core or a laminated core. The large-capacity battery core according to this embodiment further includes a conductive connection sheet 2, and the core body 1 is electrically connected to the positive electrode tab current collecting sheet and the negative electrode tab current collecting sheet via the conductive connection sheet 2, and the conductive connection sheet 2 is provided at a sealed connection location of the core shell 5. Preferably, in this embodiment, an adhesive is provided at the connection location of the conductive connection sheet 2 with the core shell 5, and the adhesive fixes and seals the conductive connection sheet 2 and the core shell 5, thereby preventing electrolyte leakage from the connection location of the conductive connection sheet 2 with the core shell 5.

[0054] Example 3 As shown in Figures 5 to 7, this embodiment proposes a large-capacity battery, which includes a large-capacity battery box 10, a parallel connection bus bar 8, and 25 large-capacity battery cores arranged to be stacked in order from bottom to top in the electrolyte chamber of the large-capacity battery box 10. Two parallel connection bus bars 8 are arranged on the outside of the large-capacity battery cores, and the positive electrode tab current collecting sheets of the 25 battery cores are connected in parallel to one parallel connection bus bar 8, and the negative electrode tab current collecting sheets of the 25 battery cores are connected in parallel to the other parallel connection bus bar 8. The top end of the large-capacity battery box 10 is open, and the large-capacity battery box A combination top cover 13 is attached to the top opening of box 10, and two electrode poles 12 are provided on combination top cover 13. These two electrode poles are a positive pole and a negative pole, respectively. The positive pole is connected to a parallel connection bus bar 8 connected to a positive electrode tab current collecting sheet, and the negative pole is connected to a parallel connection bus bar 8 connected to a negative electrode tab current collecting sheet. When electrolyte is poured into the electrolyte chamber of large-capacity battery box 10 and conduit 4 is opened, the electrolyte in the electrolyte chambers of the 25 large-capacity battery cores communicates with the electrolyte in the electrolyte chamber of large-capacity battery box 10 via conduit 4, so that the large-capacity battery cores and large-capacity battery box 10 share the same electrolyte. The electrolyte chamber of the large-capacity battery box refers to the part of the interior of the large-capacity battery box excluding the space where the large-capacity battery cores are placed.

[0055] It is particularly important to note that the material of the core shell 5 in this embodiment is one or a combination of two or more selected from polyformaldehyde, polyvinyl chloride, polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate and polyester resin.

[0056] Preferably, the large-capacity battery according to this embodiment further includes a pressure bracket 7 having 25 mounting grooves arranged in order from bottom to top, with one large-capacity battery core mounted in each mounting groove, and the tab current collecting sheets 3 extending to the outside of the mounting grooves to connect to the parallel connection bus bars 8. After the large-capacity battery cores are mounted in the mounting grooves, the large-capacity battery cores are placed together with the pressure bracket 7 in the electrolyte chamber of the large-capacity battery box 10.

[0057] Preferably, in this embodiment, when a tab current collecting sheet 3 is connected to each of the opposing sides of the core body 1, the mounting groove becomes a through groove, and the tab current collecting sheets 3 on both sides extend outward from openings on both sides of the mounting groove; alternatively, when a tab current collecting sheet 3 is disposed on one side of the core body 1, the mounting groove is not a through groove but opens on only one side, and both tab current collecting sheets 3 extend outward from the same opening; the number of mounting grooves can be specifically set according to the number of large-capacity battery cores, and corresponds one-to-one to the number of large-capacity battery cores.

[0058] In the large-capacity battery according to this embodiment, a pressure release port 14 is provided in the combination top cover 13, and a pressure release component is attached to the pressure release port 14, which communicates with the electrolyte chamber of the large-capacity battery box 10. Preferably, the pressure release port 14 according to this embodiment can function as a liquid injection hole when injecting electrolyte into the electrolyte chamber of the large-capacity battery box 10. Preferably, the pressure release component according to this embodiment is a pressure release valve 11 or an explosion-proof membrane. [Explanation of symbols]

[0059] 1 - core body, 2 - conductive connection sheet, 3 - tab current collecting sheet, 4 - conduit, 41 - thin weak groove, 42 - tension ring, 5 - core shell, 6 - sealing cap, 7 - pressure bracket, 8 - parallel connection bus bar, 9 - conduit tension wire, 10 - large-capacity battery box, 11 - pressure release valve, 12 - pole, 13 - combination top cover, 14 - pressure release port.

Claims

1. A method for manufacturing a battery, comprising: a step of assembling the wound cells or laminated cells that constitute the battery core to produce a battery core, and then performing chemical formation and capacity grading; During the crimping process of the core shell of the battery core, first crimp the four sides, then inject the electrolyte into the electrolyte chamber of the core body through the conduit, and after the injection is completed, seal the conduit so that the conduit communicates with the electrolyte chamber of the core body, thus forming the battery core; a step of grouping the battery cores according to one or more of the following: capacity, internal resistance, voltage, and self-discharge; connecting the battery cores in the same group in parallel and placing them in a battery box; and then performing a secondary liquid injection so that the electrolyte in the battery cores and the electrolyte in the battery box pass through each other; and then sealing and capacity grading; Including, The specific process by which the electrolyte in the battery core and the electrolyte in the battery box become mutually liquid-permeable is as follows: a dissolvable sheet that is soluble in the electrolyte is provided on the core shell of the battery core, and after the secondary injection, the dissolvable sheet is dissolved by the electrolyte in the battery box, allowing the electrolyte in the battery core and the electrolyte in the battery box to become mutually liquid-permeable.

2. 2. The method for manufacturing a battery according to claim 1, wherein the wound or stacked cell of the battery core comprises at least one wound or stacked core.

3. 3. The method for manufacturing a battery according to claim 2, wherein the battery core manufactured by the at least one wound core or laminated core is classified according to one or more of capacity, internal resistance, voltage, and self-discharge, specifically into Class A, Class B, and Class C.

4. 4. The method for manufacturing a battery according to claim 3, further comprising the steps of: placing the assembled battery cores in a battery box, carrying out a secondary injection; sealing the injection holes of the batteries after the secondary injection; and rating the capacity of the batteries after sealing.

5. 5. The method for manufacturing a battery according to claim 4, wherein the battery core comprises a core shell, the core shell being made of a plastic material, and the core shell having a protruding conduit disposed therein.

6. 6. The method for manufacturing a battery according to claim 5, wherein the battery core further comprises a core body, the core shell being coated on the outside of the core body, and the conduit communicating with an electrolyte chamber of the core body.

7. 7. The battery manufacturing method according to claim 6, wherein the plastic material has a melting point exceeding 130°C and is one or a combination of two or more selected from the group consisting of polyformaldehyde, polyvinyl chloride, polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyester resin.

8. 2. The battery manufacturing method according to claim 1, wherein connecting the battery cores in the same group in parallel specifically includes placing the battery cores on a pressure bracket, stacking the battery cores in order from bottom to top in an electrolyte chamber of a battery box, and connecting the battery cores in parallel using a parallel connection bus bar.

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