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 manufacturing method for a large-capacity battery and a large-capacity battery. [Background technology]

[0002] Generally, the maximum capacity of commercially available prismatic lithium iron phosphate batteries is 400Ah, and the maximum capacity of cylindrical batteries is not more than 100Ah. However, with the rise of new energy vehicles and new energy public transport vehicles, the demand for lithium-ion battery capacity is increasing. When manufacturing large-capacity lithium batteries, multiple cores must be connected in parallel, and large-capacity batteries often have problems such as battery heat generation, overcharging, and poor consistency during use. At the same time, when multiple cores are connected in parallel, the performance parameters of the cores, such as capacity, resistance, voltage, and self-discharge, often vary, or if one of the cores has a quality problem, the performance of the entire large-capacity battery is affected, and the consistency of the cores after parallel connection is poor, which causes the performance of the large-capacity battery to be unstable and the waste rate to be high; in addition, most of the existing large-capacity lithium batteries are connected in parallel and then uniformly injected with electrolyte, which causes the overall working performance of the large-capacity lithium battery to be poor. 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 difficult quality control, poor consistency, unstable performance, and high waste rate of existing large-capacity lithium batteries.

[0004] According to the method of the present application, after one injection, the batteries are formed, capacity graded, and classified, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box and then re-injected with electrolyte, thereby improving the consistency of each parallel-connected cell of the large-capacity battery, and 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 produce a battery core, and then performing chemical formation and capacity grading; grouping each battery core according to one or more of capacity, internal resistance, voltage, and self-discharge, connecting battery cores in the same group in parallel and placing them in a large-capacity battery box, performing secondary electrolyte injection 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 sealing and capacity grading.

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

[0008] Furthermore, the battery cores manufactured by 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, combine at least one A class with an A class, combine B class with a B class, remove the packaging of the battery cores, and put 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 electrolyte injection is performed. After the secondary electrolyte injection, the electrolyte injection hole of the large-capacity battery is sealed, and after sealing, the large-capacity battery is assigned a capacity rating.

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

[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] Further, 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] Additionally, the conduit has a sealed distal opening, a weakened groove disposed in an outer wall thereof, and a tension ring disposed at the distal end.

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

[0016] Furthermore, connecting the battery cores in the same group in parallel specifically includes placing the multiple battery cores on a pressure bracket, stacking the multiple battery cores sequentially from bottom to top in the electrolyte chamber of the large-capacity battery box, and connecting the multiple large-capacity battery cores in parallel by 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 injection, 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 chamber 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, injecting electrolyte into the electrolyte chamber of the large-capacity battery box, and attaching a pressure release component to the injection port of the large-capacity battery box after the injection 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 application can provide the following beneficial effects:

[0021] 1. The manufacturing method of the large-capacity battery according to the present application includes the steps of assembling the wound cells or stacked cells that constitute the large-capacity battery core to produce a battery core, 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 and the electrolyte in the large-capacity battery box to pass through each other, and then sealing and capacity grading. According to the method of the present application, the batteries are formed, capacity graded, and classified after one injection, and multiple batteries of the same grade can be connected in parallel and placed in a large-capacity battery box before being re-injected, which improves the consistency of each parallel-connected cell of the large-capacity battery, as well as improving the efficiency of quality control and battery quality of the large-capacity battery.

[0022] 2. In the manufacturing method of the large-capacity battery according to the present application, 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 placed in the electrolyte chamber 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 after parallel connection of large-capacity battery cores.

[0023] 3. The large-capacity battery core according to the method of the present application comprises a core shell, and the core shell is made of plastic material; the plastic material can significantly reduce the manufacturing cost of lithium batteries, and the product quality is the same as that of existing products. The core shell is provided with a protruding conduit, which can facilitate communication between the electrolyte chamber of the core shell and the outside.

[0024] 4. The large-capacity battery core according to the method of the present application comprises a core body, a core shell is coated on the outside of the core body, and a conduit is connected to 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; a pulling ring is provided at the end of the conduit; during use, the pulling ring can break the conduit from the weak groove, so that the electrolyte chamber of the core body in the core shell can be connected to 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 through the conduit, so that the electrolyte chambers of the large-capacity battery cores and the electrolyte chamber of the large-capacity battery box share the electrolyte, thereby further improving the performance of the large-capacity lithium battery; at the same time, even if one of the large-capacity battery cores is damaged, the other multiple large-capacity battery cores can still be conductive and function normally under the connection action of the parallel connection busbar.

[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 from one another. In addition, it also effectively prevents damage to the large-capacity battery caused by improper connection and alignment during the parallel connection process 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 lid located above the large-capacity battery box, and a pressure release component is attached to the pressure release port. The pressure release component is connected to 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 completed, the pressure release component is attached to the pressure release port. If gas is generated due to thermal runaway of the large-capacity battery, the pressure release component can easily evacuate the gas and release the pressure.

[0028] Additional advantages, objectives 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 the study and practice of the present application. [Brief description 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 drawings necessary for the description of the embodiments or the existing technology will be briefly described below. Needless to say, the drawings referred to 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 producing a large-capacity battery according to the present application. [Diagram 2] FIG. 1 is a schematic diagram showing the configuration of a large-capacity core body in a method according to a second embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram 2 showing the configuration of a large-capacity battery core in a method according to Example 2 of the present application. [Figure 4] FIG. 3 is a schematic diagram showing the configuration of a large-capacity battery core in a method according to Example 2 of the present application. [Diagram 5] FIG. 11 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 application. [Figure 6] FIG. 11 is a schematic diagram showing connections of parallel connection bus bars in a method according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a schematic diagram showing the configuration of a parallel-connected large-capacity battery in a method according to Example 2 of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0032] For large-capacity batteries, the consistency of resistance, capacity, voltage, and self-discharge of each wound core or laminated core connected in parallel inside the battery is an important index, and if a wound core or laminated core with poor consistency is used, the battery capacity will not reach the standard, the battery will heat up or overcharge, poor consistency, and other various defects will easily occur. Based on this, a manufacturing method for a large-capacity battery is proposed in this application.

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

[0034] Step 101: Assemble the wound cells or laminated cells that constitute the large-capacity battery core separately to form a battery core, and then perform chemical formation and capacity grading. The 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: Group each battery core according to one or more of capacity, internal resistance, voltage and self-discharge, and combine the battery cores in the same group, connect them in parallel and put them into a large-capacity battery box.

[0036] Step 103: A secondary electrolyte 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 performed.

[0037] The above-mentioned wound or laminated cell of the 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, and then chemical formation and capacity grading are performed; the battery core made from at least one wound or laminated core is classified according to one or more of capacity, internal resistance, voltage, and self-discharge; the battery core made from at least one wound or laminated core is divided into A grade, B pole, C grade or higher grades according to the above grades. The C grade is discarded, at least one A grade and A grade are combined, and B grade and B grade are combined, the battery core is unwrapped, and placed in a large-capacity battery box. After being placed in the large-capacity battery box, a secondary injection is performed, and after the secondary injection, the injection hole of the large-capacity battery is sealed, and after sealing, the capacity of the large-capacity battery is graded.

[0038] Before the secondary injection, the battery core needs to be opened (i.e., the battery core is unsealed) so that the inner chamber of the battery core communicates with the inner chamber of the large-capacity battery box, and 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, a dissolving sheet soluble in the electrolyte is provided on the shell of the battery core, and the dissolving sheet is formed when the battery core is manufactured. After the secondary injection, the dissolving sheet is dissolved by the electrolyte in the battery box, and the electrolyte in the battery core and the electrolyte in the large-capacity battery box can pass through each other. Specifically, the dissolving sheet is made of a material soluble in the electrolyte, such as polymethyl methacrylate, polyvinyl chloride, polycarbonate, or ABS plastic. In order to prevent the dissolvable sheet from dissolving in the electrolyte in the battery core before the secondary injection, an isolating membrane may be provided on one side of the dissolvable sheet facing the inside of the battery core. Although the isolating membrane 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 mutually pass through each other.

[0039] Example 1 For a large-capacity battery with a capacity of 1000Ah, 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, put into a simple soft pack, injected with electrolyte, and vacuum extracted. Then, the battery is formed and the capacity is graded. The battery is classified according to the internal resistance of 0.5mΩ≦R<0.55mΩ, 0.55mΩ≦R≦0.6mΩ, and R>0.6mΩ, and classified into three grades: A, B, and C. The battery packs are then reclassified according to the resistance range, within which the voltage difference within the group is ≦10mV and the capacity difference within the group is ≦2Ah. The batteries in the same group are connected in parallel using poles, the soft packs are removed and then compressed, placed in a large-capacity battery box and fitted with a combination top cover, and vacuum extracted, injected and sealed again to form a consistent 1000Ah large-capacity battery. The large-capacity batteries 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 assembled individually to form a battery core, which is then subjected to chemical formation and capacity grading. The cells are then divided into similar groups according to one or more of the capacity, internal resistance, voltage, and self-discharge, combined within the groups, connected in parallel, and placed in a large-capacity battery box. Further, a secondary electrolyte 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, after which the cells are sealed and capacity graded.

[0041] According to the method of this embodiment, after one injection, the batteries are chemically formed, capacity graded, and classified, and multiple batteries of the same grade are connected in parallel and placed in a large-capacity battery box and then re-injected with electrolyte, thereby improving the consistency of each parallel-connected cell of the large-capacity battery, and improving the quality control efficiency and battery quality of the large-capacity battery.

[0042] This embodiment further proposes a large-capacity battery manufactured by the chemical formation and capacity grading process of the large-capacity battery in the above embodiment. According to the large-capacity battery of this embodiment, after one injection, the battery is subjected to chemical formation, capacity grading and classification, and a number of batteries of the same grade are connected in parallel and placed in a large-capacity battery box and then re-injected with electrolyte, so that the consistency of each parallel-connected cell of the large-capacity battery is improved, and the quality control efficiency of the large-capacity battery and the battery quality are improved.

[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 position of one side of the core shell 5, a core connected to the conductive connection sheet 2 and the tab current collecting sheet 3 is placed in the mounting groove, the other side of the core shell 5 is crimped, and an electrolyte chamber of the core body 1 is formed inside the core shell 5. 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 the opening side is sealed after the electrolyte injection is completed; 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 thus the core is formed.

[0045] The cores are subjected to capacity grading, and after the capacity grading is completed, they are classified according to the capacity range, internal resistance range, self-discharge range, and voltage range; in this embodiment, those with a capacity range of 40-40.5Ah, an internal resistance range of 0.9-1mΩ, a self-discharge range of 2% per month or less, and a voltage range of 3.2±0.1V are classified as Class A; those with a capacity range of 39.5-40Ah, an internal resistance range of 1-1.1mΩ, a self-discharge range of 2%-4% per month or less, and a voltage range of 3.2±0.01V are classified as Class B; and those with a capacity range of 39.5Ah or less or 40.5Ah or more, an internal resistance range of 0.9mΩ or less or 1.1mΩ or more, a self-discharge range of 4% or more per month or less, and a voltage range other than 3.2±0.01V 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, an 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 column, and the parallel connection bus bar 8 connected to the negative electrode tab current collecting sheet is connected to the negative electrode column, 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 the conduit tension wire 9 is wound around the tension ring 42 of the conduit 4 in 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 the conduit 4 is broken from the weak groove 41 by pulling the conduit tension wire 9, and the conduit 4 is opened; alternatively, the conduit tension wire 9 is wound around the tension ring 42 of the conduit 4 in each of the large-capacity battery cores, and the conduit tension wire 9 is pulled to break the conduit 4 from the weak groove 41 by pulling the conduit tension wire 9, and the conduit is opened, and then the parallel-connected large-capacity batteries are placed in the electrolyte chamber of the large-capacity battery box 10; in this way, each electrolyte chamber of the large-capacity battery cores is connected to the electrolyte chamber of the battery box 10 through the conduit 4.

[0048] The electrolyte chamber of the large-capacity battery box 10 is evacuated by the pressure release port 14, and electrolyte is injected into the electrolyte chamber of the large-capacity battery box 10 by the injection valve, 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 includes 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 connected to 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 resin. Preferably, the plastic material in this embodiment is polypropylene.

[0051] According to this embodiment, a core body 1 has a tab current collecting sheet 3 connected to each of the opposing sides thereof, one of which is connected to a positive electrode tab current collecting sheet, and the other is connected to a negative electrode tab current collecting sheet. In use, a mounting groove is pressed on one side of the core shell 5, the core body 1 is placed in the mounting groove, the other side of the core shell 5 is crimped, the core shell 5 is made to cover the outside of the core body 1 to seal the core body 1, and an electrolyte chamber of 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, and 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 completed; alternatively, four sides are crimped during the crimping process, 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 is connected to 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 Fig. 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 by 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 portion of the core shell 5. Preferably, in this embodiment, an adhesive is provided at the connection portion of the conductive connection sheet 2 with the core shell 5, and the conductive connection sheet 2 and the core shell 5 are fixed and sealed by the adhesive, thereby preventing electrolyte leakage from the connection portion of the conductive connection sheet 2 with the core shell 5.

[0054] Example 3 As shown in FIGS. 5 to 7, in this embodiment, a large-capacity battery is proposed. The large-capacity battery includes a large-capacity battery box 10, a parallel connection bus bar 8, and 25 large-capacity battery cores arranged to be stacked 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. 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 uppermost end of the large-capacity battery box 10 is open. A combination top cover 13 is attached to the top opening of the box 10, and two poles 12 are provided on the combination top cover 13, and these two poles are a positive pole and a negative pole, respectively, and the positive pole is connected to the parallel connection bus bar 8 connected to the positive tab current collecting sheet, and the negative pole is connected to the parallel connection bus bar 8 connected to the negative tab current collecting sheet, and when an electrolyte is injected into the electrolyte chamber of the large-capacity battery box 10 and the conduit 4 is made conductive, the electrolyte in the electrolyte chambers of the 25 large-capacity battery cores communicates with the electrolyte in the electrolyte chamber of the large-capacity battery box 10 via the conduit 4, so that the large-capacity battery cores and the large-capacity battery box 10 share the electrolyte. The electrolyte chamber of the large-capacity battery box refers to the part of the inner chamber of the large-capacity battery box 10 excluding the space in which the large-capacity battery cores are placed.

[0055] It should be particularly noted 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 sequence from bottom to top, with one large-capacity battery core being mounted in each mounting groove, and the tab current collecting sheet 3 extending to the outside of the mounting groove and connected to the parallel connection bus bar 8. After the large-capacity battery core is mounted in the mounting groove, the large-capacity battery core is 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 the 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 only on 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 on the combination top cover 13, and a pressure release component is attached to the pressure release port 14, and the pressure release component 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 an 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-tensile 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 large-capacity battery, comprising: A process of assembling wound cells or laminated cells that constitute a large-capacity battery core to produce a battery core, and then performing chemical formation and capacity grading; a step of 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 secondary electrolyte injection so that the electrolyte in the battery core and the electrolyte in the large-capacity battery box pass through each other, and then sealing and capacity grading; A method for producing a large-capacity battery, comprising:

2. The method for manufacturing a large-capacity battery according to claim 1, wherein the wound or laminated cell of the large-capacity battery core includes at least one wound core or laminated core.

3. The method for manufacturing a large-capacity battery according to claim 2, characterized in that 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. The method for manufacturing a large-capacity battery according to claim 3, characterized in that: discarding C class, combining at least one A class with A class, combining B class with B class, removing the packaging of the battery core, and putting the combined battery core into a large-capacity battery box.

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

6. 6. The method for manufacturing a large-capacity battery according to claim 5, wherein the large-capacity battery core comprises a core shell, the core shell is made of a plastic material, and a protruding conduit is disposed in the core shell.

7. 7. The method for manufacturing a large-capacity battery according to claim 6, wherein 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 an electrolyte chamber of the core body.

8. 8. The method for manufacturing a large-capacity battery according to claim 7, 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.

9. 7. The method for manufacturing a large capacity battery according to claim 6, wherein the conduit has a sealed end opening, a weak groove disposed on an outer wall surface, and a tension ring disposed on the end.

10. 7. The method for producing a large-capacity battery according to claim 6, wherein the conduit is a liquid injection tube.

11. 2. The method for manufacturing a large-capacity battery according to claim 1, wherein connecting the 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 in an electrolyte chamber of a large-capacity battery box in order from bottom to top, and connecting the plurality of large-capacity battery cores in parallel by a bus bar for parallel connection.

12. Specifically, the parallel-connected large-capacity battery cores are placed in a large-capacity battery box, and then secondary injection, sealing, and capacity grading are performed. 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; A method for manufacturing a large-capacity battery according to any one of claims 6 to 11, comprising: connecting the electrolyte chamber of the large-capacity battery core with the electrolyte chamber of the large-capacity battery box; vacuum-extracting the electrolyte chamber of the large-capacity battery box; injecting electrolyte into the electrolyte chamber of the large-capacity battery box; and attaching a pressure release component to the injection port of the large-capacity battery box after the injection is completed.

13. 13. The method for opening the conduit as claimed in claim 12, characterized in that: a conduit pulling wire is wound around a 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 to open the conduit.

14. A large capacity battery, A large-capacity battery, characterized in that the large-capacity battery is manufactured by the method for manufacturing a large-capacity battery according to any one of claims 1 to 13.

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