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EP-4738483-A1 - LITHIUM PRIMARY BATTERY

EP4738483A1EP 4738483 A1EP4738483 A1EP 4738483A1EP-4738483-A1

Abstract

A lithium primary battery including a wound electrode group, and a nonaqueous electrolyte solution. The electrode group includes a positive electrode having a belt shape, and a negative electrode having a belt shape, which are spirally wound with a separator disposed between the positive electrode and the negative electrode. The positive electrode contains both manganese dioxide and fluorinated graphite. The negative electrode includes a lithium alloy. The lithium alloy contains magnesium, and the content of the magnesium in the lithium alloy is 0.01 mass% or more and 11 mass% or less.

Inventors

  • ANDO, KEITA
  • ASANO, Yuya

Assignees

  • Panasonic Intellectual Property Management Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240606

Claims (6)

  1. A lithium primary battery, comprising: a wound electrode group; and a nonaqueous electrolyte solution, wherein the electrode group includes a positive electrode having a belt shape, and a negative electrode having a belt shape, which are spirally wound with a separator disposed between the positive electrode and the negative electrode, the positive electrode contains both manganese dioxide and fluorinated graphite, the negative electrode includes a lithium alloy, the lithium alloy contains magnesium, and a content of the magnesium in the lithium alloy is 0.01 mass% or more and 11 mass% or less.
  2. The lithium primary battery according to claim 1, wherein a proportion of the fluorinated graphite in a total mass of the manganese dioxide and the fluorinated graphite is 0.1 mass% or more and 10 mass% or less.
  3. The lithium primary battery according to claim 1, wherein a proportion of the fluorinated graphite in a total mass of the manganese dioxide and the fluorinated graphite is 0.1 mass% or more and 5 mass% or less.
  4. The lithium primary battery according to any one of claims 1 to 3, wherein the content of the magnesium in the lithium alloy is 0.1 mass% or more and 1 mass% or less.
  5. The lithium primary battery according to any one of claims 1 to 3, wherein the lithium alloy further contains aluminum, and a content of the aluminum in the lithium alloy is 0.01 mass% or more and 0.5 mass% or less.
  6. The lithium primary battery according to any one of claims 1 to 3, wherein the negative electrode is a foil of the lithium alloy, and does not include a negative electrode current collector.

Description

[Technical Field] The present disclosure relates to a lithium primary battery. [Background Art] Lithium primary batteries have high energy density and low self-discharge, and are therefore used as power sources for many electronic devices. A wound electrode group of a lithium primary battery is configured by spirally winding a positive electrode having a belt shape, a negative electrode having a belt shape, and a separator disposed between the positive electrode and the negative electrode. For a negative electrode of lithium primary batteries, for example, lithium metal or lithium alloy in the form of sheet (foil) is used. Patent Literature 1 proposes "a nonaqueous electrolyte solution battery, comprising: a positive electrode including, as an active material, a mixture of manganese dioxide and fluorinated graphite; a negative electrode including, as a negative electrode material, metal lithium, or a material capable of absorbing and releasing lithium ions; and a nonaqueous electrolyte solution, wherein the fluorinated graphite is represented by a formula (CFx)n, where 1.2 ≤ x ≤ 1.4, and its weight ratio in the mixture is 0.1 to 4%". Patent Literature 2 proposes "a lithium battery, comprising: a positive electrode containing manganese dioxide, as a positive electrode active material; a negative electrode containing at least one of lithium metal and a lithium alloy, as a negative electrode active material; a porous insulator disposed between the positive electrode and the negative electrode; and an organic electrolyte, wherein the organic electrolyte contains a hydroxycarboxylic acid ester in an amount of 0.001 to 1 wt%". Patent Literature 2 discloses that "as the negative electrode active material, at least one of lithium metal and a lithium alloy is used. The lithium alloy may be, for example, an alloy of lithium and at least one metal selected from the group consisting of aluminum, tin, magnesium, indium, and calcium. The content of the metals other than lithium in the lithium alloy is preferably 0.1 to 3 wt%" ([0034]). [Citation List] [Patent Literature] Patent Literature 1: Japanese Laid-Open Patent Publication No. H7-50165Patent Literature 2: Japanese Laid-Open Patent Publication No. 2011-60655 [Summary of Invention] [Technical Problem] Patent Literature 1 discloses that, when fluorinated graphite is mixed with manganese dioxide, a reaction product generated through the reaction between the manganese dioxide and the nonaqueous electrolyte solution will be captured by the fluorinated graphite, and thus, the reaction (self-discharge) of the reaction product with lithium on the negative electrode side becomes unlikely to occur ([0012]). However, fluorinated graphite has a larger theoretical capacity than manganese dioxide. Therefore, the positive electrode capacity increases when manganese dioxide is mixed with fluorinated graphite. As a result, in a lithium primary battery in which metal lithium or lithium alloy in the form of sheet (foil) is used as a negative electrode, part of the negative electrode may be chipped or fractured in the end stage of discharge, and the discharge performance may degrade in some cases. One possible solution would be to change the capacity balance between the positive and negative electrodes, but rather, it is desirable to increase the overall battery capacity without causing the discharge performance to degrade. [Solution to Problem] One aspect of the present disclosure relates to a lithium primary battery, including: a wound electrode group; and a nonaqueous electrolyte solution, wherein the electrode group includes a positive electrode having a belt shape, and a negative electrode having a belt shape, which are spirally wound with a separator disposed between the positive electrode and the negative electrode, the positive electrode contains both manganese dioxide and fluorinated graphite, the negative electrode includes a lithium alloy, the lithium alloy contains magnesium, and a content of the magnesium in the lithium alloy is 0.01 mass% or more and 11 mass% or less. [Advantageous Effects of Invention] According to the present disclosure, it is possible to improve the discharge performance in a lithium primary battery. While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings. [Brief Description of Drawing] [FIG. 1] A front view, partially in section, of a lithium primary battery according to an embodiment of the present invention. [Description of Embodiments] Embodiments of the present disclosure will be described below by way of examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values and materials are exemplified in some cases, but ot