CN113675410A

CN113675410A - Bipolar battery substrate, bipolar plate and manufacturing method

Info

Publication number: CN113675410A
Application number: CN202110149714.9A
Authority: CN
Inventors: 丁平; 苑景春; 陈冬; 张育红; 党志敏; 刘桃松; 陈加成; 段玉娟
Original assignee: Zhejiang Narada Power Source Co Ltd
Current assignee: Zhejiang Narada Power Source Co Ltd
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2021-11-19
Anticipated expiration: 2041-02-03
Also published as: CN113675410B

Abstract

A bipolar battery base, a bipolar plate and a manufacturing method thereof. The bipolar battery matrix comprises a high polymer material serving as a matrix main body and a plurality of interwoven conductive fibers distributed inside and/or on the surface of the matrix main body; wherein the length of the partial conductive fibers is greater than or equal to the thickness of the bipolar battery matrix, and at least one end of the partial conductive fibers is exposed on one of the two opposite sides of the matrix. Wherein the mass ratio of the plurality of conductive fibers to the matrix is (1-50): (50-99).

Description

Bipolar battery substrate, bipolar plate and manufacturing method

Technical Field

The invention relates to the technical field of bipolar batteries, in particular to a bipolar battery substrate, a bipolar plate and a manufacturing method thereof.

Background

As a battery with a novel structure, the bipolar battery is characterized in that positive and negative active material materials are coated on two surfaces of the same electrode, so that the current passing path is short, the distribution is more uniform, and the utilization rate of the active material can be improved. Meanwhile, the bipolar battery structure cancels the structures of a lug, a bus bar, a polarized pole and the like in the traditional battery, the weight of the battery is further reduced, and the energy density can be improved by more than 40%. Further, the bipolar battery is excellent in power characteristics and cycle characteristics. However, the bipolar battery technology has not been commercialized at present, and the main reason is that no suitable material is available for the battery substrate. The matrix of the bipolar battery is different from the grid of the traditional unipolar lead-acid storage battery. The bipolar substrate has the function of a current collector, can bear lead paste, and can also play a role in connecting two single batteries in series.

The bipolar battery was originally invented by KAPITA who directly used lead foil as the base body of the bipolar battery. Although lead foil has good conductivity and good binding with active materials as a substrate, lead has a high density and affects the specific energy of the battery. And lead is difficult to be used as a substrate for sealing, because the single shell of the bipolar battery still needs to use insulating materials such as plastic and the like, and special glue is needed to be used for combining the plastic and the lead substrate, the sealing of the bipolar battery is particularly problematic after long-term use, so that the early bipolar battery is mostly in failure due to leakage, particularly leakage among single cells of the battery, and the popularization and the use of the bipolar battery are influenced.

Later Ellis

K, etc. by TiO_xPreparation of conductive plastics from conductive ceramic materialSubstrate, TiO_xRelatively good conductivity, oxidation resistance, but TiO_xAt present, the market application is influenced due to higher production cost, the prepared conductive plastic substrate has poorer bonding force with positive and negative active substances, and a layer of lead foil needs to be additionally hot-pressed on the surface of the conductive plastic substrate, so that the production process difficulty is further increased, and the current technology still stays in a laboratory stage and cannot be produced in a large scale.

Disclosure of Invention

The invention aims to provide a bipolar battery substrate with good bonding force, a bipolar plate and a manufacturing method.

In order to solve the technical problem, the invention provides a bipolar battery matrix, which comprises a high polymer material serving as a matrix main body and a plurality of interwoven conductive fibers distributed inside and/or on the surface of the matrix main body; wherein the length of the partial conductive fibers is greater than or equal to the thickness of the bipolar battery matrix, and at least one end of the partial conductive fibers is exposed on one of the two opposite sides of the matrix. Wherein the mass ratio of the plurality of conductive fibers to the base body ranges from (1-50): (50-99).

The conductive fibers are arranged on the high polymer material as the matrix main body and distributed in the inner part and/or the surface of the matrix main body, and the mass ratio of the plurality of conductive fibers to the matrix main body is (1-50): (50-99), so that most of the surface finally contacted with the lead paste is made of high polymer materials, and the rest part is exposed conductive fibers, so that the adhesion between the bipolar battery matrix and the lead paste in the application is excellent, and the lead paste still firmly adheres to two sides of the bipolar battery matrix after being tested to freely fall for 3 times from a height of 1 meter. Furthermore, at least one end of the partially conductive fiber is exposed to one of the two opposite sides of the substrate, and the conductive fibers are interwoven with each other to ensure the conductivity between the two opposite sides of the substrate of the bipolar battery. Secondly, the length of part of the conductive fibers is set to be greater than or equal to the thickness of the bipolar battery substrate, further ensuring the conductivity between the opposite sides of the bipolar battery substrate. In addition, the matrix main body material in the application is single, no auxiliary agent is required to be added, and the process is simple.

In order to further improve the adhesion between the opposite sides of the substrate and the lead paste, a surface of each side may be provided with a bump or a grid to increase the contact area.

Optionally, the length of the partial conductive fibers is more than or equal to three times the thickness of the bipolar battery matrix. The longer the thickness of the conductive fiber relative to the substrate, the better the conductivity of the bipolar battery substrate. Optionally, the length of the partial conductive fibers is more than or equal to four times, five times, six times, seven times, ten times, fifteen times and the like of the thickness of the bipolar battery matrix. The length of the other conductive fibers may be shorter than the thickness of the bipolar battery substrate, or the length of the other conductive fibers may be equal to or greater than three times, four times, five times, six times, seven times, ten times, fifteen times, etc. the thickness of the bipolar battery substrate.

Optionally, the average diameter of the plurality of conductive fibers is 0.02mm to 0.1mm, and the average length of the plurality of conductive fibers is 1mm to 15 mm. When the thickness is larger than 15mm, the injection molding effect is affected, and the injection molding opening is easily blocked if the thickness is too long. The length of all the conductive fibers may be relatively uniform, for example, the average length of all the conductive fibers is about 15mm, or about 14mm, or about 13mm, or about 12mm, or about 11mm, or about 10mm, or about 9mm, or about 8mm, or about 7mm, or about 6mm, or about 5mm, or about 4mm, or about 3mm, or about 2mm, or about 1 mm.

The lengths of all the conductive fibers may also have different gradients. The gradient can be three, the conductive fibers with a length less than the thickness of the bipolar battery matrix account for the least weight of all the conductive fibers and less than 5%, the conductive fibers with a length greater than the thickness of the bipolar battery matrix and less than three times the thickness account for the second weight of all the conductive fibers and 5% -40%, the conductive fibers with a length greater than three times the thickness of the bipolar battery matrix account for the most weight of all the conductive fibers and 55% -95%. For example, the conductive fibers with the length of less than 1mm account for 1 percent of the mass of all the conductive fibers, the conductive fibers with the length of 1mm to 3mm account for 40 percent of the mass of all the conductive fibers, and the conductive fibers with the length of 3mm to 6mm account for 59 percent of the mass of all the conductive fibers. The lengths of all the conductive fibers in each gradient can be uniformly distributed or distributed in a gradient.

In other embodiments, there may be two gradients, with conductive fibers having a length less than three times the thickness of the bipolar battery matrix accounting for less than 5% of the weight of all the conductive fibers, and conductive fibers having a length greater than three times the thickness of the bipolar battery matrix accounting for 95% -100% of the weight of all the conductive fibers. In another possible embodiment, there may also be four, five, six or ten, even fifteen gradients. For example, the conductive fibers having average lengths of about 15mm, about 14mm, about 13mm, about 12mm, about 11mm, about 10mm, about 9mm, about 8mm, about 7mm, about 6mm, about 5mm, about 4mm, about 3mm, about 2mm, and about 1mm are distributed.

Optionally, the conductive fiber includes one or more of a lead fiber, a lead alloy fiber, a glass fiber plated with lead, a polymer fiber plated with lead, a glass fiber plated with lead, and a polymer fiber plated with lead. TiO 2_xHas good conductivity, even lower resistivity than graphite, but still has 6.7 x 10 resistivity^-4Omega m, while the resistivity of lead is only 2.07 x 10^-5Ω m, the conductivity is 1 order of magnitude higher. And lead or lead alloy and positive negative pole active material have better cohesion, need not in addition the conductive plastic to cover a layer of lead foil and improve the cohesion.

Optionally, the mass ratio of the plurality of conductive fibers to the matrix body ranges from 1: (1-20). For example, 1: 1. 1: 2. 1: 3. 1: 4. 1: 5. 1: 6. 1: 7. 1: 8. 1: 9. 1: 10. 1: 11. 1: 12. 1: 13. 1: 14. 1: 15. 1: 16. 1: 17. 1: 18. 1: 19. 1: 20, etc

Optionally, the polymer material includes any one or a combination of more of ABS, PP, PPO, PVC, PA, PC, PMMA, POM, PE, TPE and TPO.

The invention also provides a bipolar plate which comprises any one of the bipolar battery matrixes, and positive lead plaster and negative lead plaster which are respectively arranged on two sides of the bipolar battery matrix.

The invention also provides a preparation method for preparing any bipolar battery matrix, which comprises the steps of uniformly mixing a plurality of conductive fibers and a high polymer material serving as a matrix main body, then carrying out injection molding, polishing two sides, and exposing the plurality of conductive fibers to obtain the bipolar battery matrix.

The invention also provides a preparation method for preparing any bipolar battery matrix, which comprises the following steps: and uniformly mixing a plurality of conductive fibers and a high polymer material serving as a matrix main body, then performing injection molding, and cutting to obtain the bipolar battery matrix.

In summary, the conductive fibers are disposed on the polymer material as the matrix main body and distributed in the interior and/or the surface of the matrix main body, and the mass ratio of the plurality of conductive fibers to the matrix main body is (1-50): (50-99), so that most of the surface finally contacted with the lead paste is made of high polymer materials, and the rest part is exposed conductive fibers, so that the adhesion between the bipolar battery matrix and the lead paste in the application is excellent, and the lead paste still firmly adheres to two sides of the bipolar battery matrix after being tested to freely fall for 3 times from a height of 1 meter. Furthermore, at least one end of the partially conductive fiber is exposed to one of the two opposite sides of the substrate, and the conductive fibers are interwoven with each other to ensure the conductivity between the two opposite sides of the substrate of the bipolar battery. Secondly, the length of part of the conductive fibers is set to be greater than or equal to the thickness of the bipolar battery substrate, further ensuring the conductivity between the opposite sides of the bipolar battery substrate.

Drawings

FIG. 1 is a schematic view of a bipolar battery substrate provided in an embodiment of the present invention;

FIG. 2 is a schematic view of a bipolar plate provided by embodiments of the present invention;

FIG. 3 is an SEM image of the surface of a bipolar battery substrate provided in an embodiment of the invention.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The "inner and/or surface" in the present invention includes: interior and surface, interior or surface.

The ranges recited in this disclosure are inclusive.

The direction of the connecting line of the shortest distance on the opposite sides of the bipolar battery substrate in the present invention is the thickness direction of the bipolar battery substrate.

Example one

10 parts by weight of pure lead fibers are uniformly mixed with 90 parts by weight of an ABS base material main body, wherein the average diameter of the pure lead fibers is 0.02mm, and the average length of the pure lead fibers is 3.0 mm. And (3) grinding the surface of the plastic sheet with the length of 200mm, the width of 200mm and the thickness of 1mm by using an injection molding machine, and exposing the lead fibers on two sides by using 180# sandpaper to obtain the bipolar battery matrix 4, wherein the structure is shown in the schematic diagram of fig. 1, and the lead fibers 1 are distributed in the base material main body 2 in an interlaced mode or on the surface of the base material main body. The surface SEM image is shown in FIG. 3, the lead fibers are criss-cross, and part of the lead fibers are exposed on the surface of the substrate. The bipolar battery matrix tested had a weight of 46.19g and the relevant parameters were as follows, with a density of 1.14g/cm³Resistivity 6.07 x 10^-4Omega m, tensile strength 44.0MPa, bending strength 70.5 MPa.

As shown in FIG. 2, a positive electrode lead paste 3 having a thickness of 1.2mm, a length of 180mm and a width of 180mm was applied to one surface of the prepared bipolar battery substrate 4, and then the plastic sheet was carefully turned over, and a negative electrode lead paste 5 having a thickness of 1.0mm, a length of 180mm and a width of 180mm was applied to the other surface. All the positive and negative electrode lead pastes are common lead-acid battery lead pastes.

And (3) performing curing treatment on the plastic sheet coated with the lead paste according to the common lead-acid battery plate process, firstly placing the plastic sheet in a high-temperature high-humidity environment with the humidity of 100% at 85 ℃ for 24 hours, and then drying the plastic sheet at 85 ℃ for 24 hours to obtain the bipolar plate.

The obtained bipolar plate freely falls 3 times from a height of 1 meter above the ground, and positive and negative lead pastes are firmly attached to the plastic sheet.

Example two

20 parts by weight of pure lead fibers are uniformly mixed with 80 parts by weight of ABS base material, wherein the average diameter of the pure lead fibers is 0.02mm, and the average length of the pure lead fibers is 3.0 mm. Testing the plastic matrix with weight of 50.28g and related parameters as follows, and density of 1.28g/cm³Resistivity 2.74 x 10^-4Omega m, tensile strength 32.7MPa, and bending strength 55.4 MPa.

Coating a layer of positive lead plaster with the thickness of 1.2mm, the length of 180mm and the width of 180mm on one surface of a plastic sheet, then carefully overturning the plastic sheet, and coating a layer of negative lead plaster with the thickness of 1.0mm, the length of 180mm and the width of 180mm on the other surface, wherein all the positive and negative lead plasters are common lead-acid battery lead plasters.

The plastic sheet coated with the lead paste is subjected to curing treatment according to the common lead-acid battery plate process, and is firstly placed in a high-temperature high-humidity environment with the humidity of 100% at 85 ℃ for 24 hours and then dried at 85 ℃ for 24 hours. Obtaining the bipolar plate.

EXAMPLE III

Example three is basically the same as example one except that the base material is PP plastic and 10 parts by weight of lead fibers are mixed with 90 parts by weight of the PP base material. The weight of the prepared plastic matrix is 43.14g, the related parameters are as follows, and the density is 1.08g/cm³Resistivity 7.12 x 10^-4Omega m, tensile strength 35.6MPa, bending strength 56.8 MPa.

The bipolar plate prepared in the same way freely falls 3 times from a height of 1 meter above the ground, and positive and negative lead pastes are firmly attached to the plastic sheet.

Example four

Example four the same as example one except that the mass ratio of the lead fibers to the ABS base material was adjusted by mixing 5 parts by weight of the lead fibers with 95 parts by weight of the ABS plasticAnd (6) mixing. The weight of the prepared plastic matrix is 44.10g, the related parameters are as follows, and the density is 1.10g/cm³Resistivity 1.13 x 10^-3Omega m, tensile strength of 48.3MPa and bending strength of 79.6 MPa.

The bipolar plate prepared in the same way is subjected to free falling for 3 times from a height of 1 meter above the ground, the negative lead paste is firmly attached to the plastic sheet, and the positive lead paste has a small amount of falling-off phenomenon.

EXAMPLE five

Example five is basically the same as example one except that the mass ratio of the lead fiber to the ABS base material is adjusted and 40 parts by weight of the lead fiber is mixed with 60 parts by weight of the ABS plastic. The weight of the prepared plastic matrix is 65.89g, the related parameters are as follows, and the density is 1.65g/cm³Resistivity 1.05 x 10^-4Omega m, tensile strength 28.3MPa, bending strength 39.6 MPa.

EXAMPLE six

The six basic points of the embodiment are the same as those of the embodiment, except that the lead fiber adopts lead-tin alloy with tin content of 1.5 percent by mass, and the diameter and the length of the lead fiber are unchanged. The weight of the prepared plastic matrix is 50.26g, the related parameters are as follows, and the density is 1.28g/cm³Resistivity 2.53 x 10^-4Omega m, tensile strength 31.6MPa, bending strength 54.4 MPa.

EXAMPLE seven

The seventh example is basically the same as the second example except that the lead fibers have an average length of 1mm and the fiber diameter is unchanged. The weight of the prepared plastic matrix is 50.31g, the related parameters are as follows, and the density is 1.28g/cm³Resistivity 8.87 x 10^-4Omega m, tensile strength 31.6MPa, bending strength 56.8 MPa.

Example eight

Example eight is essentially the same as example two except that the lead fibres have an average length of 5mm and the fibre diameter is constant. The weight of the prepared plastic matrix is 50.24g, the related parameters are as follows, and the density is 1.28g/cm³Resistivity 2.16 x 10^-4Omega m, tensile strength 33.4MPa, bending strength 49.8 MPa.

Example nine

Example nine is basically the same as example two except that the lead fibres have an average diameter of 0.05mm and a constant length. The weight of the prepared plastic matrix is 50.19g, the related parameters are as follows, and the density is 1.28g/cm³Resistivity 3.16 x 10^-4Omega m, tensile strength 29.4MPa, and bending strength 47.8 MPa.

Example ten

The example was substantially the same as the example except that the lead fibers had an average diameter of 0.1mm and a constant length. The weight of the prepared plastic matrix is 50.11g, the related parameters are as follows, and the density is 1.28g/cm³Resistivity 3.22 x 10^-4Omega m, tensile strength 27.4MPa, bending strength 46.2 MPa.

EXAMPLE eleven

Example eleven is essentially the same as example one except that of 10 parts of lead fiber, 1 part of the fiber having an average length of less than 1mm, 3 parts of the fiber having an average length of 1mm to 3mm, and 6 parts of the fiber having an average length of more than 3mm are used. The weight of the prepared plastic matrix is 44.39g, the related parameters are as follows, and the density is 1.16g/cm³Resistivity 4.07 x 10^-4Omega m, tensile strength 45.0MPa, and bending strength 72 MPa.

Example twelve

The eleventh embodiment is basically the same as the first embodiment, except that the average length of the lead fibers is 15mm, plastic blocks with the length of 200mm, the width of 200mm and the thickness of 15mm are manufactured by an injection molding machine, plastic sheets with the required thickness are cut according to requirements, the bipolar battery substrate cut from the middle is not required to be ground, the lead fibers on the two sides are exposed, the bipolar battery substrate is obtained, and the parameters and the performances of the obtained substrate and the bipolar plate are similar to those of the first embodiment.

In summary, except for the fourth embodiment, the resistivity of the bipolar battery substrate prepared by the present application is less than or equal to 8.87 × 10^-4The conductivity is good. Moreover, most of the bipolar battery matrix in the application is made of high polymer materials, so that the corrosion resistance is good, and the short circuit inside the battery is prevented. The composite material also has good chemical stability, and the matrix does not participate in the reaction of the anode and the cathode of the battery. From the free fall tests of the various examples it can be seen that there must be good bonding between the substrate and the active material (lead paste) to ensure that the electrochemical reaction of the cell proceeds smoothly. In addition, the composite material has high mechanical strength, is easy to process and is not easy to deform.

It will be understood by those skilled in the art that in the present disclosure, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships that are based on those shown in the drawings, which are merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus the above-described terms should not be construed as limiting the invention.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A bipolar battery substrate, comprising:

a polymer material as a matrix main body;

a plurality of interwoven electrically conductive fibers distributed within and/or on a surface of the matrix body;

wherein the length of part of the conductive fibers is greater than or equal to the thickness of the bipolar battery matrix, and at least one end of the part of the conductive fibers is exposed on one of two opposite sides of the matrix;

wherein the mass ratio of the plurality of conductive fibers to the base body ranges from (1-50): (50-99).

2. The bipolar battery substrate of claim 1, wherein the length of the partially conductive fibers is equal to or greater than three times the thickness of the bipolar battery substrate.

3. The bipolar battery substrate of claim 1, wherein a portion of the conductive fibers have a length that is shorter than a thickness of the bipolar battery substrate.

4. The bipolar battery substrate of claim 1, wherein the plurality of conductive fibers have an average diameter of 0.02mm to 0.1mm and an average length of 1mm to 15 mm.

5. The bipolar battery substrate of claim 1, wherein the conductive fibers comprise one or more of lead fibers, lead alloy fibers, glass fibers plated with lead, polymeric fibers plated with lead, glass fibers plated with lead alloy, polymeric fibers plated with lead alloy.

6. The bipolar battery substrate according to claim 1, wherein a mass ratio of the plurality of conductive fibers to the substrate body ranges from 1: (1-20).

7. The bipolar battery substrate of claim 1, wherein all of the conductive fibers have a uniform length distribution or a gradient length distribution.

8. A bipolar plate comprising:

the bipolar battery substrate according to any one of claims 1 to 7;

and the positive lead plaster and the negative lead plaster are respectively arranged on two sides of the bipolar battery matrix.

9. A production method for producing the bipolar battery substrate according to any one of claims 1 to 7, the production method comprising:

and uniformly mixing the plurality of conductive fibers and a high polymer material serving as a matrix main body, then performing injection molding, polishing two sides, and exposing the plurality of conductive fibers to obtain the bipolar battery matrix.

10. A production method for producing the bipolar battery substrate according to any one of claims 1 to 7, the production method comprising:

and uniformly mixing the plurality of conductive fibers and a high polymer material serving as a matrix main body, then performing injection molding, and cutting to obtain the bipolar battery matrix.