Bipolar battery current collector and manufacturing method of battery

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a bipolar battery current collector and a manufacturing method of a battery, the current collector is made of lead-carbon alloy with specific components, comprises 0.003%-0.03% of single-walled carbon nanotubes, 0.005%-0.015% of copper, 0.2%-0.5% of tin, 0.0004%-0.0012% of aluminum and the balance of lead, and does not contain cadmium, arsenic, antimony and calcium. The current collector is prepared through a specific manufacturing process, and the specific manufacturing process comprises the steps of preparation of a single-walled carbon nanotube, preparation of a single-walled carbon nanotube mother alloy, preparation of a lead-carbon alloy, casting of the current collector and the like. Cylindrical protrusions which are regularly arranged are designed on a single side plate of the current collector, so that the contact area and the bonding strength of the lead paste and the current collector in the curing process are increased. According to the invention, the specific energy of the battery is improved, the cycle life of the battery is prolonged, the production cost is reduced, and the sealing and stable operation of the battery are realized through a specific battery assembly method.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a bipolar battery current collector and a method for manufacturing the battery. Background Art

[0002] Bipolar batteries are relative to traditional lead-acid batteries. In traditional lead-acid batteries, one grid of a single plate corresponds to one polarity, which is unipolar, that is, either positive or negative. Bipolar plates refer to the use of a current collector, and the two sides of the current collector are coated with positive lead paste and negative lead paste respectively, that is, one plate has two polarities.

[0003] like Figure 1 As shown, the structure of the bipolar battery plate is: a positive lead paste 2 is applied to the positive plate on one side of the conductive bipolar current collector 1, and a negative lead paste 3 is applied to the negative plate on the other side, and the bipolar electrode is separated from the adjacent opposite polarity electrode by an AGM separator paper 6. During the electrochemical reaction, electrons are transmitted in the plate, and ions move in the electrolyte 5 between the substrates. The minimum cell voltage of a lead-acid battery is 2V, and the minimum cell of a bipolar battery is composed of a bipolar plate plus a single positive plate 4 and a single negative plate 5 to form a 4V bipolar battery, and a 2NV bipolar battery can be composed of N bipolar plates plus a single positive plate 4 and a single negative plate 5.

[0004] Compared with traditional lead-acid batteries, bipolar batteries have the following characteristics: 1. The lead used in the grid and busbars of traditional lead-acid batteries is omitted, and the maximum lead saving can reach 30%. 2. The manufacturing process of grids, busbars, poles and bridges is omitted, which can reduce production costs by at least 20%. 3. The active material is more evenly distributed, with low resistance and no acid stratification, which significantly slows down sulfation during the cycle. 4. High specific energy, the specific energy of bipolar batteries is more than 1.5 times that of traditional lead-acid batteries. 5. Long cycle life, which is more than 50% longer than that of traditional lead-acid batteries.

[0005] The biggest advantage of the lead-calcium alloy cast grid or current collector used in traditional lead-acid batteries is that it has excellent maintenance-free performance and a small amount of hydrogen evolution due to its high hydrogen evolution overpotential. However, due to the presence of calcium, the interface between the lead-calcium alloy grid and the active material is prone to generate lead sulfate, calcium sulfate, or an oxide barrier layer with semiconductor characteristics, which increases the internal resistance of the battery, reduces the charge and discharge performance of the lead-acid battery, and is prone to early capacity loss. Summary of the invention

[0006] The object of the present invention is to provide a bipolar battery current collector and a method for manufacturing a battery, using a lead-carbon alloy as the material of the current collector. The material is free of cadmium, arsenic, antimony and calcium. It is formed by casting. Cold cracks and pores are not easily generated during the casting process. The chemical properties are stable, so as to solve the problems in the prior art raised in the above background technology.

[0007] To achieve the above-mentioned purpose, the present invention proposes the following technical solution on one hand: a bipolar battery current collector, the bipolar battery current collector is made of a lead-carbon alloy, the lead-carbon alloy includes the following components in mass fractions: single-walled carbon nanotubes: 0.003%-0.03%; copper: 0.005%-0.015%; tin: 0.2%-0.5%; aluminum: 0.0004%-0.0012%; the balance is lead, and the lead-carbon alloy does not contain cadmium, arsenic, antimony and calcium.

[0008] On the other hand, the present invention provides a method for manufacturing a battery with a bipolar battery current collector, the method comprising the following steps: preparing a single-walled carbon nanotube master alloy; preparing a lead-carbon alloy; casting the current collector; mixing and curing; externalizing the plate; and assembling the battery.

[0009] Preferably, the method further comprises preparing single-walled carbon nanotubes, wherein the preparing single-walled carbon nanotubes comprises: preparing the single-walled carbon nanotubes by adopting an organic catalytic cracking method; and purifying and drying the single-walled carbon nanotubes.

[0010] Preferably, the preparation method of the single-walled carbon nanotube master alloy comprises: using an anionic surfactant to dissolve the purified and dried single-walled carbon nanotubes to prepare a solution; adding copper sulfate or copper nitrate or a mixture thereof to the solution for reaction; forming a black powdery substance after crystallization and drying; mixing the black powdery substance with copper oxide and tin oxide and reducing it with aluminum at 600-900°C under vacuum or argon protection.

[0011] Preferably, the method for preparing the single-walled carbon nanotube master alloy further comprises: mixing the purified and dried single-walled carbon nanotubes with copper oxide and tin oxide in proportion; and reducing them with aluminum at 600-900° C. under vacuum or argon protection.

[0012] Preferably, the preparation method of the lead-carbon alloy comprises: co-melting the single-walled carbon nanotube master alloy and lead at a weight ratio of 1:10-1:15 at 500-600°C; and obtaining the single-walled carbon nanotube battery alloy after sufficient stirring.

[0013] Preferably, the paste mixing and curing include: uniformly applying the lead paste on both sides of the current collector by mechanical coating; curing the current collector filled with wet lead paste in a curing device according to a curing process that meets the process requirements; the free lead content of the bipolar green plate after curing is ≤3%, and the water content is ≤1%.

[0014] Preferably, the externalization forming comprises: externalizing the cured bipolar plate by externalization forming; the lead dioxide content of the positive lead paste of the bipolar plate after the forming is 88% to 92%, and the lead oxide content of the negative lead paste is ≤5%.

[0015] Preferably, the battery assembly includes: separating the bipolar plates, single positive plates and single negative plates after formation with AGM separator paper; assembling them into electrode groups and loading them into battery slots; injecting epoxy resin glue so that the glue wraps the current collectors, the single positive plates and the single negative plates; adding electrolytes that meet the process density; sealing the battery and completing the assembly.

[0016] Preferably, the battery assembly further comprises: connecting the assembled semi-finished battery to a charging and discharging power source, and charging and discharging the semi-finished battery according to a charging process; and cleaning the battery and then removing it from the production line to complete the production of the bipolar battery.

[0017] Technical effects and advantages of the present invention: Compared with the prior art, the present invention provides a bipolar battery current collector and a method for manufacturing a battery, which have the following advantages:

[0018] The present invention uses a lead-carbon alloy as a current collector material. The material is cadmium-free, arsenic-free, antimony-free, and calcium-free. It is formed by casting, and is not prone to cold cracking and pores during the casting process. It has stable chemical properties. By using a lead-carbon alloy current collector with a specific composition and an optimized manufacturing process, it is possible to reduce the amount of lead used, reduce production costs, improve the uniformity of active material distribution, increase battery specific energy, extend cycle life, improve maintenance-free performance, enhance conductivity and mechanical strength, and optimize the battery assembly process, thereby significantly improving the overall performance and service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a bipolar battery plate in the prior art;

[0020] Figure 2 is a schematic diagram of the structure of the current collector in the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the battery container of the present invention;

[0022] Figure 4 It is a schematic diagram of the structure of the battery cover of the present invention;

[0023] Figure 5 It is a structural schematic diagram of the liquid injection hole of the present invention;

[0024] Figure 6 It is a schematic diagram of the structure of the bipolar plate of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] The present invention provides a bipolar battery current collector, which adopts a lead-carbon alloy. The alloy includes the following components by mass fraction: a single-walled carbon nanotube with a mass content of 0.003%, a copper content of 0.005%, a tin content of 0.2%, an aluminum content of 0.0004%, and the balance being lead.

[0028] The lead-carbon alloy also requires a single-walled carbon nanotube aqueous solution, and then a copper sulfate solution is added to the solution. After the unnecessary components are dried and crystallized, the solution is mixed with copper oxide and tin oxide and stirred evenly. Aluminum is added and vacuum smelted and reduced at 900±5°C to obtain a single-walled carbon nanotube master alloy, which is added to lead at a ratio of 1:10 and smelted at 540±5°C. After stirring evenly, a lead-carbon alloy liquid is obtained, which is cast into a pre-prepared mold and cooled to form a current collector of the present invention. Figure 2 shown.

[0029] In addition, the method for preparing the single-walled carbon nanotube aqueous solution is a mature prior art and will not be described in detail here.

[0030] After the current collector casting is completed, the bipolar battery paste mixing process is entered. The positive and negative lead pastes prepared by the paste mixing are evenly applied on both sides of the current collector. Since the single-side plate of the current collector is designed with regularly arranged cylindrical protrusions 7, the combination of the lead paste and the current collector during the curing process of the bipolar plate is increased to form the bipolar plate of the present invention. The cast bipolar battery current collector has the characteristics of being tightly combined with the positive and negative lead pastes, a large contact surface area between the positive and negative lead pastes and the current collector, and good mechanical strength of a single-cell bipolar plate.

[0031] After the bipolar plates are externalized, the battery is assembled. Figure 3 As shown, the bipolar plate 11, the separator 6, the single positive plate 4 and the single positive plate 5 are installed in the battery container 8 according to the corresponding polarity, and the epoxy resin 13 is injected into the gap between the battery container 8 and the current collector 11, the single positive plate 4 and the negative plate 5, as shown in FIG. Figure 2 The holes on both sides of the current collector 1 are more conducive to the penetration of the epoxy resin 13 and strengthen the combination of the current collector 1 and the epoxy resin 13. After the current collector 1, the single positive plate 4 and the negative plate 5 are cured by the epoxy resin, Figure 4 The middle battery cover 12 is inverted, and epoxy resin glue 13 is injected. Figure 3 The semi-finished battery is inverted into the battery cover 12 covered with epoxy resin glue 13, and the pole 9 is placed in the pole position of the battery cover 12. The battery slot edge 10 and the pole 9 are wrapped with epoxy resin glue 13 to achieve a sealing effect. There is no cross-cell or air leakage between the single cells in the battery slot. After the pole sleeve 14 on the battery slot is milled to the process height, the terminal 15 is placed, and the terminal 15 and the pole 9 are welded firmly to form a welding point 16, and there is no cold welding or false welding. After adding the electrolyte that meets the process density through the injection hole 17, a safety valve 19 is covered on each injection hole 17, and then the battery cover 18 is bonded with carbon tetrachloride to complete the battery assembly and injection.

[0032] In addition, the method of forming the bipolar plate by externalization is a mature existing technology and will not be described in detail here.

[0033] Connect the charging and discharging power supply connecting wires to the positive and negative terminals 15 and proceed according to the charging process. After the charging is completed, the bipolar battery is fully charged and can be used offline.

[0034] Another aspect of the present invention provides a method for manufacturing a battery with a bipolar battery current collector, the method comprising the following steps: preparing a single-walled carbon nanotube master alloy; preparing a lead-carbon alloy; casting the current collector; mixing and curing the paste; externalizing the plate; and assembling the battery.

[0035] The metallic single-walled carbon nanotubes with a diameter of 0.33-5 nm are prepared by organic catalytic cracking method, and the single-walled carbon nanotubes are purified and dried;

[0036] Preparation of single-walled carbon nanotube master alloy: The preparation method is selected from method 1 or method 2:

[0037] Method 1: using an anionic surfactant to dissolve the purified and dried single-walled carbon nanotubes to prepare a single-walled carbon nanotube solution, adding copper sulfate or copper nitrate or a mixture of the two to the solution and mixing them thoroughly to react, forming a black powdery substance after crystallization and drying, taking the black powdery substance and copper oxide and tin oxide according to the above ratio, and reducing it with aluminum at 600-900° C. under vacuum or argon protection to prepare a single-walled carbon nanotube master alloy;

[0038] Method 2: Mix the purified and dried single-walled carbon nanotubes with copper oxide and tin oxide in proportion, and reduce them with aluminum at 600-900°C under vacuum or argon protection to obtain a single-walled carbon nanotube master alloy;

[0039] Preparation of battery nano-lead carbon grid: Single-walled carbon nanotube master alloy and lead are eutectic at 500-600°C in a weight ratio of 1:10-1:15, and stirred thoroughly to obtain a single-walled carbon nanotube battery alloy. The alloy is cast to obtain a single-walled carbon nanotube bipolar current collector 1.

[0040] A vacuum paste mixing machine is used to produce lead paste that meets the process requirements, and the lead paste is evenly applied to both sides of the bipolar current collector 1 by a mechanical plate coating method. The current collector filled with wet lead paste is cured in a curing device according to a curing process that meets the process requirements. After curing, the free lead content of the bipolar green plate is ≤3%, and the water content is ≤1%.

[0041] The cured bipolar plate is externally formed by external forming, and the lead dioxide content of the positive lead paste of the bipolar plate after forming is 88% to 92%, and the lead oxide content of the negative lead paste is ≤5%.

[0042] The bipolar plate 20, a single positive plate 4 and a single negative plate 5 after formation are separated by AGM separator paper 6, assembled into a pole group, and loaded into a battery tank 8. First, epoxy resin glue 13 is injected into the battery tank 8 to wrap the current collector 1, the single positive plate 4 and the single negative plate 5. Then, the battery tank is placed in a drying kiln for 1 hour to accelerate the curing of the epoxy resin glue 13. After the glue is cured, a certain amount of epoxy resin glue 13 is injected into the inverted battery cover 12, and the battery tank 8 loaded with the pole group is sealed with the battery cover 12. The epoxy resin glue 13 is accelerated to solidify by drying in a drying kiln for 1 hour. After the glue is solidified, it is allowed to stand for 12 hours to restore the temperature inside the battery. The electrolyte (containing S After the mixture is heated to 40 ℃ and 10 ℃, the safety valve 19 is put on and the battery cover 18 is glued on.

[0043] The assembled semi-finished battery is connected to a charging and discharging power source, and the semi-finished battery is charged and discharged according to the charging process. After the charging and discharging is completed, the battery is cleaned and taken off the production line to complete the production of the bipolar battery.

[0044] Example 2

[0045] The present invention provides a bipolar battery current collector, which adopts a lead-carbon alloy. The alloy includes the following components by mass fraction: a single-walled carbon nanotube with a mass content of 0.02%, a copper content of 0.01%, a tin content of 0.3%, an aluminum content of 0.001%, and the balance being lead.

[0046] The lead-carbon alloy also requires a single-walled carbon nanotube aqueous solution, and then a copper sulfate solution is added to the solution. After the unnecessary components are dried and crystallized, the solution is mixed with copper oxide and tin oxide and stirred evenly. Aluminum is added and vacuum smelted and reduced at 900±5°C to obtain a single-walled carbon nanotube master alloy, which is added to lead at a ratio of 1:10 and smelted at 540±5°C. After stirring evenly, a lead-carbon alloy liquid is obtained, which is cast into a pre-prepared mold and cooled to form a current collector of the present invention. Figure 2 shown.

[0047] In addition, the method for preparing the single-walled carbon nanotube aqueous solution is a mature prior art and will not be described in detail here.

[0048] After the current collector casting is completed, the bipolar battery paste mixing process is entered. The positive and negative lead pastes prepared by the paste mixing are evenly applied on both sides of the current collector. Since the single-side plate of the current collector is designed with regularly arranged cylindrical protrusions 7, the combination of the lead paste and the current collector during the curing process of the bipolar plate is increased to form the bipolar plate of the present invention. The cast bipolar battery current collector has the characteristics of being tightly combined with the positive and negative lead pastes, a large contact surface area between the positive and negative lead pastes and the current collector, and good mechanical strength of a single-cell bipolar plate.

[0049] Example 3

[0050] The present invention provides a bipolar battery current collector, which adopts a lead-carbon alloy. The alloy includes the following components by mass fraction: a single-walled carbon nanotube with a mass content of 0.03%, a copper content of 0.015%, a tin content of 0.5%, an aluminum content of 0.0012%, and the balance being lead.

[0051] The lead-carbon alloy also requires a single-walled carbon nanotube aqueous solution, and then a copper sulfate solution is added to the solution. After the unnecessary components are dried and crystallized, the solution is mixed with copper oxide and tin oxide and stirred evenly. Aluminum is added and vacuum smelted and reduced at 900±5°C to obtain a single-walled carbon nanotube master alloy, which is added to lead at a ratio of 1:10 and smelted at 540±5°C. After stirring evenly, a lead-carbon alloy liquid is obtained, which is cast into a pre-prepared mold and cooled to form a current collector of the present invention. Figure 2 shown.

[0052] In addition, the method for preparing the single-walled carbon nanotube aqueous solution is a mature prior art and will not be described in detail here.

[0053] After the current collector casting is completed, the bipolar battery paste mixing process is entered. The positive and negative lead pastes prepared by the paste mixing are evenly applied on both sides of the current collector. Since the single-side plate of the current collector is designed with regularly arranged cylindrical protrusions 7, the combination of the lead paste and the current collector during the curing process of the bipolar plate is increased to form the bipolar plate of the present invention. The cast bipolar battery current collector has the characteristics of being tightly combined with the positive and negative lead pastes, a large contact surface area between the positive and negative lead pastes and the current collector, and good mechanical strength of a single-cell bipolar plate.

[0054] In summary, the current collector in this application adopts a lead-carbon alloy with a specific composition, including single-walled carbon nanotubes (0.003%-0.03%), copper (0.005%-0.015%), tin (0.2%-0.5%), aluminum (0.0004%-0.0012%), and the balance is lead, and does not contain cadmium, arsenic, antimony and calcium. The current collector is prepared by a specific manufacturing process, including the preparation of single-walled carbon nanotubes, the preparation of single-walled carbon nanotube master alloys, the preparation of lead-carbon alloys and the casting of current collectors. Regularly arranged cylindrical protrusions are designed on the single-side plate of the current collector to increase the contact area and bonding strength between the lead paste and the current collector during the curing process. The invention improves the specific energy and cycle life of the battery, reduces the production cost, and achieves the sealing and stable operation of the battery through a specific battery assembly method.

[0055] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bipolar battery current collector, characterized in that: The bipolar battery current collector is made of a lead-carbon alloy, and the lead-carbon alloy includes the following components in mass fractions: Single-walled carbon nanotubes: 0.003%-0.03%; Copper: 0.005%-0.015%; Tin: 0.2%-0.5%; Aluminum: 0.0004%-0.0012%; The balance is lead, and the lead-carbon alloy does not contain cadmium, arsenic, antimony and calcium.

2. A method for manufacturing a battery with a bipolar battery current collector according to claim 1, characterized in that: The method comprises the following steps: preparing single-walled carbon nanotube master alloy; Preparation of lead-carbon alloy; Casting of current collector; Paste and curing; Externalization of the plates; Assembly of the battery.

3. The method for manufacturing a battery according to claim 1, characterized in that: The invention also includes preparing single-walled carbon nanotubes, wherein the preparing single-walled carbon nanotubes includes: Single-walled carbon nanotubes were prepared by catalytic cracking of organic matter; The single-walled carbon nanotubes are purified and dried.

4. The method for manufacturing a battery according to claim 3, characterized in that: The preparation method of the single-walled carbon nanotube master alloy comprises: The purified and dried single-walled carbon nanotubes are dissolved by an anionic surfactant to prepare a solution; adding copper sulfate or copper nitrate or a mixture thereof to the solution for reaction; After crystallization and drying, a black powdery substance is formed; The black powdery substance is mixed with copper oxide and tin oxide and reduced with aluminum at 600-900° C. under vacuum or argon protection.

5. The method for manufacturing a battery according to claim 4, characterized in that: The method for preparing the single-walled carbon nanotube master alloy further comprises: The purified and dried single-walled carbon nanotubes are mixed with copper oxide and tin oxide in proportion; Reduce with aluminum at 600-900°C under vacuum or argon protection.

6. The method for manufacturing a battery according to claim 4, characterized in that: The preparation method of the lead-carbon alloy comprises: The single-walled carbon nanotube master alloy and lead are eutectic at a weight ratio of 1:10-1:15 at 500-600° C.; After sufficient stirring, the single-walled carbon nanotube battery alloy is obtained.

7. The method for manufacturing a battery according to claim 6, characterized in that: The paste and curing include: Use mechanical coating to evenly apply lead paste on both sides of the current collector; The current collector filled with wet lead paste is cured in a curing device according to a curing process that meets the process requirements; The free lead content of the cured bipolar green plate is ≤3% and the water content is ≤1%.

8. The method for manufacturing a battery according to claim 7, characterized in that: The externalization comprises: The cured bipolar plate is externalized by externalization; The lead dioxide content of the positive lead paste of the bipolar plate after formation is 88% to 92%, and the lead oxide content of the negative lead paste is ≤5%.

9. The method for manufacturing a battery according to claim 8, characterized in that: The battery assembly comprises: The bipolar plates, single positive plates and single negative plates after formation are separated by AGM separator paper; Assemble into pole groups and install into battery slots; Injecting epoxy resin glue so that the glue wraps the current collector, the single positive plate and the single negative plate; Add electrolyte that meets the process density; Seal the battery and complete the assembly.

10. The method for manufacturing a battery according to claim 9, characterized in that: The battery assembly further comprises: Connect the assembled semi-finished battery to a charging and discharging power source, and charge and discharge the semi-finished battery according to the charging process; After cleaning the battery, it is taken off the production line, completing the production of bipolar batteries.

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