Low molecular weight sodium polyacrylate binder alkaline manganese battery negative electrode and preparation method thereof

Abstract

The present invention belongs to the field of battery preparation, and specifically relates to a low molecular weight sodium polyacrylate binder alkaline manganese battery negative electrode and a preparation method thereof. The negative electrode of the alkaline manganese battery is mainly made of zinc paste, and the zinc paste is composed of zinc powder, electrolyte, polyacrylic acid cross-linked resin and low molecular weight sodium polyacrylate (PAANa-L). The preparation steps are as follows: (1) 100g of zinc powder is mixed with 0.1-1g of polyacrylic acid cross-linked resin and stirred evenly; (2) 0.1-1g of sodium polyacrylate is added to the mixture in (1) and continued to stir thoroughly; (3) the mixed material in (2) is added to 40-60g of electrolyte, continuously stirred, and accompanied by negative pressure degassing to form a qualified zinc paste. The present invention selects PAANa with low molecular weight to fundamentally solve the problem of product drawing, and at the same time, it is matched with polyacrylate products with high viscosity to ensure product viscosity while having a stable diffusion effect.

Description

Technical Field

[0001] The invention belongs to the field of battery preparation, and particularly relates to a low-molecular-weight sodium polyacrylate binder alkaline manganese battery negative electrode and a preparation method thereof. Background Art

[0002] Sodium polyacrylate (PAANa) is a new type of functional polymer electrolyte. Its applications are closely related to its molecular weight. Low molecular weight sodium polyacrylate (PAANa-L) is primarily used as a pigment dispersant and water treatment agent, while medium molecular weight sodium polyacrylate (PAANa-M) is primarily used as a thickener, viscosity stabilizer, and water retention agent. Higher molecular weight sodium polyacrylate (PAANa-DK) is primarily used as a flocculant and thickener.

[0003] In the alkaline manganese battery industry, PAANa also plays a role in thickening and bonding. The PAANa used are all high molecular weight products, which give the products the functions of thickening, bonding, and stabilizing the framework. However, in addition to having high viscosity, high molecular weight PAANa will also cause the thickened object to be accompanied by stringing. The stringing phenomenon becomes more serious as the molecular weight and viscosity of the product increase, which to a certain extent limits the application scope of high molecular weight PAANa. Summary of the Invention

[0004] In order to solve the stringing problem of sodium polyacrylate used in alkaline manganese batteries, the present invention selects PAANa with low molecular weight to fundamentally solve the stringing problem of the product. At the same time, it is combined with polyacrylate products with high viscosity to ensure product viscosity while having a stable diffusion effect.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A low molecular weight sodium polyacrylate binder alkaline manganese battery negative electrode and a preparation method thereof, wherein the negative electrode of the alkaline manganese battery is mainly made of zinc paste, characterized in that the zinc paste comprises zinc powder, electrolyte, polyacrylic acid cross-linked resin and low molecular weight sodium polyacrylate (PAANa-L).

[0007] Furthermore, the formula of the zinc paste is 100 parts of zinc powder, 40-60 parts of electrolyte, 0.1-1 part of polyacrylic acid cross-linked resin, and 0.1-1 part of PAANa-L.

[0008] Furthermore, the electrolyte concentration is 20%-40%, and the molecular weight of the PAANa-L is 5*10 3 -5*10 4 g / mol.

[0009] Furthermore, the method for preparing the negative electrode of the alkaline manganese battery with the low molecular weight sodium polyacrylate binder comprises the following steps:

[0010] (1) Mix 100 g of zinc powder with 0.1-1 g of polyacrylic acid cross-linked resin and stir evenly;

[0011] (2) adding 0.1-1 g of sodium polyacrylate to the mixture in (1) and continuing to stir thoroughly;

[0012] (3) Add the mixed materials in (2) into 40-60 g of electrolyte, stir continuously, and degas under negative pressure to form a qualified zinc paste.

[0013] Furthermore, the pressure of the negative pressure degassing is 45 to 55 KPa.

[0014] Beneficial effects of the present invention:

[0015] In the prior art, the zinc paste binder uses high molecular weight sodium polyacrylate, which has a molecular weight of 10 6 -10 7 g / mol, and there is a wire drawing phenomenon during use; the present invention studies the binder of the negative electrode zinc paste of alkaline manganese battery and uses low molecular weight sodium polyacrylate (PAANa-L) with a molecular weight of 5*10 3 -5*10 4 , avoiding drawing; and by adding polyacrylic acid cross-linking resin, the zinc paste structure is stabilized. DETAILED DESCRIPTION

[0016] In order to deepen the understanding of the present invention by those skilled in the art, the present invention will be further described below with reference to specific embodiments.

[0017] Example 1

[0018] A low molecular weight sodium polyacrylate binder alkaline manganese battery negative electrode and a preparation method thereof, wherein the negative electrode of the alkaline manganese battery is mainly made of zinc paste, characterized in that the zinc paste comprises zinc powder, electrolyte, polyacrylic acid cross-linked resin and low molecular weight sodium polyacrylate (PAANa-L).

[0019] Furthermore, the formula of the zinc paste is 100 parts of zinc powder, 40-60 parts of electrolyte, 0.1-1 part of polyacrylic acid cross-linked resin, and 0.1-1 part of PAANa-L.

[0020] Furthermore, the electrolyte concentration is 20%-40%, and the molecular weight of the PAANa-L is 5*10 3 -5*10 4 g / mol.

[0021] The preparation of the negative electrode of the alkaline manganese battery with a low molecular weight sodium polyacrylate binder comprises the following steps:

[0022] (1) Mix 100 g of zinc powder with 0.3 g of polyacrylic acid cross-linked resin and stir evenly;

[0023] (2) adding 0.6 g of sodium polyacrylate having a molecular weight of 40,000 g / mol to the mixture in (1) and continuing to stir thoroughly;

[0024] (3) The mixed materials in (2) were added into 55 g of 30% electrolyte, stirred continuously, and degassed under negative pressure to form a qualified zinc paste without stringing.

[0025] Example 2

[0026] The preparation of the negative electrode of the alkaline manganese battery with a low molecular weight sodium polyacrylate binder comprises the following steps:

[0027] (1) Mix 100 g of zinc powder with 0.3 g of polyacrylic acid cross-linked resin and stir evenly;

[0028] (2) adding 0.6 g of sodium polyacrylate having a molecular weight of 6000 g / mol to the mixture in (1) and continuing to stir thoroughly;

[0029] (3) The mixed materials in (2) were added into 55 g of 30% electrolyte, stirred continuously, and degassed under negative pressure to form a qualified zinc paste without stringing.

[0030] Example 3

[0031] The preparation of the negative electrode of the alkaline manganese battery with a low molecular weight sodium polyacrylate binder comprises the following steps:

[0032] (1) Mix 100 g of zinc powder with 0.3 g of polyacrylic acid cross-linked resin and stir evenly;

[0033] (2) adding 0.6 g of sodium polyacrylate having a molecular weight of 4000 g / mol to the mixture in (1) and continuing to stir thoroughly;

[0034] (3) The mixed materials in (2) were added into 55 g of 30% electrolyte, stirred continuously, and degassed under negative pressure to form a qualified zinc paste. The zinc paste had low viscosity and poor stability.

[0035] Example 4

[0036] The preparation of the negative electrode of the alkaline manganese battery with a low molecular weight sodium polyacrylate binder comprises the following steps:

[0037] (1) Mix 100 g of zinc powder with 0.3 g of polyacrylic acid cross-linked resin and stir evenly;

[0038] (2) adding 0.6 g of sodium polyacrylate having a molecular weight of 48,000 g / mol to the mixture in (1) and continuing to stir thoroughly;

[0039] (3) The mixed materials in (2) were added into 55 g of 30% electrolyte, stirred continuously, and degassed under negative pressure to form a qualified zinc paste with no stringiness and a stable structure.

[0040] Example 5

[0041] The preparation of the negative electrode of the alkaline manganese battery with a high molecular weight sodium polyacrylate (PAANa-DK) binder comprises the following steps:

[0042] (1) Mix 100 g of zinc powder with 0.3 g of polyacrylic acid cross-linked resin and stir evenly;

[0043] (2) adding 0.6 g of sodium polyacrylate having a molecular weight of 60,000 g / mol to the mixture in (1) and continuing to stir thoroughly;

[0044] (3) The mixed materials in (2) were added into 55 g of 30% electrolyte, stirred continuously, and degassed under negative pressure to form a qualified zinc paste, which showed a wire drawing phenomenon.

[0045] The zinc paste prepared in Example 1 and the zinc paste prepared in Example 5 were respectively injected into the semi-finished batteries of this workshop, and the discharge was observed under 1.5W / 0.65W, 1000mA and 250mA, and 3.9Ω continuous discharge and intermittent discharge. The new charge and stored discharge data are shown in Table 1 below.

[0046] Table 1 Comparison of battery discharge performance between PAANa-L zinc paste in Example 1 and PAANa-DK zinc paste in Example 5

[0047]

[0048]

[0049] The data in the table above demonstrates that, when low-molecular-weight PAANa-L replaces the existing high-molecular-weight PAANa-DK in the workshop, the discharge performance of the battery is compared. Under high-current 1.5W / 0.65W discharge conditions, the low-molecular-weight PAANa-L performs better than the high-molecular-weight PAANa-DK, regardless of whether the battery is new, stored at high temperature, or stored at room temperature. Furthermore, the PAANa-L storage rate is higher than that of the PAANa-DK. Under all other discharge conditions, the low-molecular-weight PAANa-L battery discharge performance is higher than that of the existing PAANa-DK to varying degrees, and the amount of gassing after discharge is also less.

[0050] The above test results show that low molecular weight PAANa-L can also be used as a zinc paste binder in alkaline zinc-manganese batteries.

Claims

1. Low molecular weight sodium polyacrylate binder alkaline manganese battery negative electrode, characterized in that, The main material of the negative electrode of the alkaline manganese battery is zinc paste, which is composed of zinc powder, electrolyte, polyacrylic acid cross-linked resin and low molecular weight sodium polyacrylate; The formula of the zinc paste is 100 parts zinc powder, 40-60 parts electrolyte, 0.1-1 parts polyacrylic acid cross-linked resin, 0.1-1 parts low molecular weight sodium polyacrylate; the molecular weight of the low molecular weight sodium polyacrylate is 5*10 3 -5*10 4 g / mol.

2. The alkaline manganese battery negative electrode according to claim 1, wherein: The electrolyte concentration is 20%-40%.

3. The method for preparing the negative electrode of an alkaline manganese battery according to claim 1, wherein: The steps include: (1) Mix 100g of zinc powder with 0.1-1g of polyacrylic acid cross-linked resin and stir evenly; (2) Add 0.1-1 g of sodium polyacrylate to the mixture in (1) and continue stirring thoroughly; (3) Add the mixed materials in (2) into 40~60g of electrolyte, stir continuously, and degas under negative pressure to form a qualified zinc paste.

4. The method for preparing the negative electrode of an alkaline manganese battery according to claim 3, wherein: The pressure of the negative pressure degassing is 45~55kPa.

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