Method for improving liquid retention rate of binder for alkaline manganese battery and testing method

Abstract

The invention relates to the technical field of testing, in particular to a method for improving the liquid retention rate of a binder for an alkaline manganese battery and a testing method. The testing method comprises the following steps: (1) weighing a container a, and recording the mass m0; (2) weighing a container b, recording the mass M0, weighing a certain mass of a binder, recording the mass as M1, and then adding the binder into the container b; (3) completely immersing the container a and the container b in the liquid solvent for 24 hours, separating the container a and the container b from the liquid solvent, suspending the container a and the container b in the air, and standing for 24 hours; and weighing the mass of the container, respectively recording the mass as m1 and M2, and calculating the 24-hour liquid retention rate of the binder through publicity. The testing method is simple in operation process and step, required equipment is relatively common, the dependence degree on an experimental environment is low, the testing method is not easily influenced by external factors, and the testing method is suitable for being implemented in various complicated operation environments.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and in particular to a method and testing method for improving the liquid retention rate of binders used in alkaline manganese batteries. Background Technology

[0002] Liquid Retention Factor (LRF), or liquid retention rate, refers to the ratio of the effective volume of electrolyte inside a battery to the total volume of electrode pores, usually expressed as a percentage. Industry standards require a liquid retention factor of ≥85% for high-quality power batteries (refer to GB / T 31485-2015). This parameter directly affects the battery's ion conduction efficiency: if the liquid retention factor is too low (e.g., <70%), the electrolyte cannot fully wet the electrodes, leading to increased internal resistance and capacity decay; if it is too high (e.g., >95%), it may cause leakage risks. For example, CATL has optimized its design to control the liquid retention factor of its NCM811 battery at 88%~92%, increasing its cycle life to over 3000 cycles.

[0003] Common core factors affecting the electrolyte retention coefficient include the following: 1. Electrolyte properties: Viscosity: Low-viscosity electrolytes (e.g., 1.0~1.5 mPa·s) penetrate electrode pores more easily, but have a high risk of volatilization; Wettability: Electrolytes containing fluorinated carbonates can reduce the contact angle to below 15° (compared to 30° for ordinary electrolytes), significantly improving the wetting rate (Journal of Power Sources, 2021). 2. Electrode material characteristics: Porosity: The ideal porosity for graphite anodes is 30%~35%, and excessively high porosity will reduce electrolyte retention uniformity; Surface coating: Al2O3-coated cathode materials can increase electrolyte adsorption by about 20% (Nature Energy, 2020). 3. Battery design and process, electrolyte injection amount: 2.5~3.5g of electrolyte needs to be injected per Ah cell. After Tesla 4680 battery adopts dry electrode process, the electrolyte injection amount is reduced by 15%; compaction density: when the positive electrode compaction is >3.4g / cm³, the rate of decrease in liquid retention coefficient is accelerated.

[0004] For the negative electrode of alkaline manganese batteries, the liquid retention rate of the binder is one of the key factors affecting the battery's performance. Good liquid retention capacity can improve the battery's discharge capacity, lifespan, and stability. Therefore, in actual production, testing and evaluating the liquid retention capacity of the raw material binder is crucial, and the test results have significant guiding significance for adjusting the production process formulation. Based on the above, this invention proposes a method and test method for improving the liquid retention rate of binders used in alkaline manganese batteries, which can effectively solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method and test method for improving the liquid retention rate of binders used in alkaline manganese batteries.

[0006] To achieve the above objectives, the present invention provides a method for testing the liquid retention rate of binders for alkaline manganese batteries, the method comprising the following steps:

[0007] (1) Weigh a container a that can absorb liquid using a weighing device and record the mass m0;

[0008] (2) Weigh another container b that can absorb liquid using a weighing device and record the mass M0. Weigh a certain mass of adhesive and record it as M1. Then add the adhesive to the container b that can absorb liquid.

[0009] (3) Completely immerse containers a and b of the absorbable liquid from steps (1) and (2) in the liquid solvent, soak for 24 hours, then remove the containers of absorbable liquid from the liquid solvent and suspend them in the air for 24 hours.

[0010] (4) Weigh the containers of the absorbable liquids mentioned above using a weighing device. The mass of the containers of absorbable liquids without the binder is recorded as m1, and the mass of the containers of absorbable liquids with the binder is recorded as M2. Calculate the 24-hour liquid retention rate of the binder using the following formula.

[0011] Calculation formula:

[0012] .

[0013] Preferably, the containers a and b for the absorbable liquid in step (1) and step (2) are of equal volume, similar density, and made of the same material.

[0014] Preferably, the container for the absorbable liquid in step (1) and step (2) includes one of the following materials or forms: tea bag, sponge, paper ball, cotton, beaker.

[0015] Preferably, in one embodiment, the container for the absorbent liquid is a tea bag.

[0016] Preferably, the binder in step (2) is an binder for alkaline manganese batteries.

[0017] Preferably, the liquid solvent in step (3) includes one or more of the following: colloidal solution, alkaline solution, acid solution, metal ion-containing solution, organic solvent, and battery electrolyte.

[0018] Preferably, in one embodiment, the liquid solvent is an alkaline manganese battery electrolyte.

[0019] Preferably, in one embodiment, the alkaline manganese battery electrolyte is a potassium hydroxide solution containing saturated zinc oxide.

[0020] The present invention also provides a method for improving the liquid retention rate of binders for alkaline manganese batteries, wherein the binder for alkaline manganese batteries is composed of sodium carboxymethyl cellulose and polyacrylic acid, and the mass ratio of the two is 1:1.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The testing method of the present invention has simple operation steps, requires relatively common equipment, has low dependence on the experimental environment, is not easily affected by external factors, and is suitable for implementation in various complex working environments.

[0023] 2. The testing method of the present invention is easy to operate, requires low skill level from operators, is highly operable and repeatable, and is suitable for application in various industrial fields.

[0024] 3. The working principle of the test method of the present invention conforms to the rules of natural science, and the measurement results are highly accurate, which is conducive to improving the quality control of adhesives, especially the quality control of adhesive liquid retention rate, and has the prospect of application and promotion. Detailed Implementation

[0025] Example 1

[0026] Determination of liquid retention rate of adhesive A:

[0027] (1) Weigh a tea bag a using a small analytical balance and record the mass m0;

[0028] (2) Weigh another tea bag b with a small analytical balance and record the mass M0. Weigh a certain mass of adhesive and record it as M1. Then add the adhesive to the container b that can absorb liquid.

[0029] (3) Hang tea bag a and tea bag b on the telescopic hook, extend the hook until they are completely submerged in potassium hydroxide solution containing saturated zinc oxide, soak for 24 hours, adjust the length of the hook, raise the tea bags until they are completely out of the solution, and suspend them in the air for 24 hours.

[0030] (4) After no more droplets are dripped, weigh tea bag a and tea bag b in a small analytical balance and record them as m1 and M2 respectively. Calculate the liquid retention rate of the adhesive in 24 hours.

[0031] Calculation formula:

[0032]

[0033] The results are shown in Table 2.

[0034] Examples 2-5

[0035] The same tests as in Example 1 were performed on Examples 2-5, respectively, to measure the liquid retention rate of adhesives B / C / D / E. The results are shown in Tables 4-6.

[0036] Table 1 Adhesive weight ratio

[0037]

[0038] Table 2

[0039]

[0040] Table 3

[0041]

[0042] Table 4

[0043]

[0044] Table 5

[0045]

[0046] Table 6

[0047]

[0048] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for testing the liquid retention rate of binders used in alkaline manganese batteries, characterized in that, The testing method includes the following steps: (1) Weigh a container a that can absorb liquid using a weighing device and record the mass m0; (2) Weigh another container b that can absorb liquid using a weighing device and record the mass M0. Weigh a certain mass of adhesive and record it as M1. Then add the adhesive to the container b that can absorb liquid. (3) Completely immerse containers a and b of the absorbable liquid from steps (1) and (2) in the liquid solvent, soak for 24 hours, then remove the containers of absorbable liquid from the liquid solvent and suspend them in the air for 24 hours. (4) Weigh the containers of the absorbable liquids mentioned above using a weighing device. The mass of the containers of absorbable liquids without the binder is recorded as m1, and the mass of the containers of absorbable liquids with the binder is recorded as M2. Calculate the 24-hour liquid retention rate of the binder using the following formula. Calculation formula: 。 2. The test method according to claim 1, characterized in that, The containers a and b for the absorbable liquid in step (1) and step (2) are of equal volume, similar density, and made of the same material.

3. The test method according to claim 1, characterized in that, The container for absorbable liquid in step (1) and step (2) includes one of the following materials or forms: tea bag, sponge, paper ball, cotton, beaker.

4. The test method according to claim 3, characterized in that, The container for the absorbent liquid is a tea bag.

5. The test method according to claim 1, characterized in that, The binder used in step (2) is an binder for alkaline manganese batteries.

6. The test method according to claim 1, characterized in that, The liquid solvent in step (3) includes one or more of the following: colloidal solution, alkaline solution, acid solution, metal ion-containing solution, organic solvent, and battery electrolyte.

7. The test method according to claim 6, characterized in that, The liquid solvent is an alkaline manganese battery electrolyte.

8. The test method according to claim 7, characterized in that, The electrolyte in the alkaline manganese battery is a potassium hydroxide solution containing saturated zinc oxide.

9. A method for improving the liquid retention rate of binders used in alkaline manganese batteries, characterized in that, The method specifies that the binder for alkaline manganese batteries is composed of sodium carboxymethyl cellulose and polyacrylic acid.

10. The method according to claim 9, characterized in that, The mass ratio of sodium carboxymethyl cellulose and polyacrylic acid in the binder for alkaline manganese batteries is 1:1.

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