Secondary battery

Abstract

To provide a secondary battery capable of preventing a decrease in active material in an electrode and a decrease in battery capacity according to the charge / discharge state.SOLUTION: A secondary battery 100 includes a pair of a positive electrode layer 101 and a negative electrode layer 102, and magnetic field generating means 104 provided on the outside of the positive electrode layer 101 and the negative electrode layer 102, which generates a magnetic field in a predetermined direction in the positive electrode layer 101 and the negative electrode layer 102.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a secondary battery. [Background technology]

[0002] Patent Document 1 describes a secondary battery containing a material that generates a magnetic field in at least one of the positive electrode and the negative electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-56045 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a magnetic material is mixed into a battery as in Patent Document 1, the active material in the electrodes is reduced, which poses a problem of a tendency for the battery capacity to decrease. [Means for solving the problem]

[0005] In one embodiment of the secondary battery, a magnetic field is generated to cause metal cations to diffuse in a predetermined direction. [Effects of the Invention]

[0006] According to the secondary battery of the present disclosure, it is possible to prevent the active material in the electrodes from decreasing depending on the charge / discharge state, and to prevent a decrease in battery capacity. [Brief explanation of the drawings]

[0007] [Figure 1] 1A and 1B are a perspective view and a cross-sectional view showing a schematic configuration of a secondary battery according to a first embodiment; [Figure 2] 1 is a cross-sectional view showing a detailed configuration of a secondary battery according to a first embodiment. [Figure 3]FIG. 10 is a cross-sectional view showing a schematic configuration of a secondary battery according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a perspective view and a cross-sectional view showing a schematic configuration of a secondary battery according to the first embodiment. In FIG. 1, a battery cell 110 includes a positive electrode layer 101, a negative electrode layer 102, and a separator 103. The secondary battery 100 includes the positive electrode layer 101, the negative electrode layer 102, the separator 103, and a magnetic field generating means 104. For example, as shown in the upper perspective view of FIG. 1, the secondary battery 100 includes a plurality of battery cells 110-1 to 110-n.

[0009] The positive electrode layer 101 is a positive electrode layer containing a positive electrode active material. Here, the positive electrode active material refers to a substance that participates in the absorption and desorption of charge carriers (for example, lithium ions in a lithium ion secondary battery) on the positive electrode side.

[0010] The negative electrode layer 102 is a negative electrode layer containing a negative electrode active material. Here, the negative electrode active material refers to a substance that participates in the absorption and desorption of charge carriers (for example, lithium ions in a lithium ion secondary battery) on the negative electrode side.

[0011] The separator 103 is in contact with the positive electrode layer 101 on a first main surface and in contact with the negative electrode layer 102 on a second main surface. The separator 103 is configured to allow charge carriers such as lithium ions to move between the positive electrode layer 101 and the negative electrode layer 102.

[0012] The magnetic field generating means 104 is provided outside the positive electrode layer 101 and the negative electrode layer 102. In other words, the magnetic field generating means 104 is provided outside the positive electrode layer 101 and the negative electrode layer 102. The magnetic field generating means 104 generates a magnetic field in a predetermined direction in the positive electrode layer 101 and the negative electrode layer 102. Here, the magnetic field direction is the same as the movement direction of Li ions in the secondary battery 100 during charging and discharging. For example, as shown in FIG. 1, the magnetic field generating means 104 generates magnetic field lines from the positive electrode layer 101 to the negative electrode layer 102. For example, the magnetic field generating means 104 is a combination of magnets provided outside the positive electrode layer 101 and the negative electrode layer 102. The magnets may be either permanent magnets or electromagnets. The magnetic field generating means 104 is preferably provided outside the plurality of battery cells 110-1 to 110-n.

[0013] Next, the principle of the lithium-ion secondary battery of the present disclosure will be described. FIG. 2 is a cross-sectional view showing a schematic configuration of the secondary battery according to the first embodiment. FIG. 2 is a cross-sectional view showing a detailed configuration of the secondary battery according to the first embodiment. In FIG. 2, the negative electrode layer 102 includes a foil 121 and a negative electrode active material 122. As shown in FIG. 2, the diffusion direction of Li ions in the negative electrode layer 102 is the same as the direction of the magnetic field. When Li ions pass between particles in the negative electrode layer 102, pressing the negative electrode active material 122 with Lorentz force 201 makes it easier for the Li ions to pass through, shortening the liquid phase diffusion distance (202) and promoting the diffusion of Li ions retained on the surface of the negative electrode layer 102.

[0014] The positive electrode layer 101 is also a single-layer electrode, similar to the negative electrode layer 102. (Thickly coated electrodes are highly effective.)

[0015] As described above, the secondary battery of the first embodiment can prevent the active material in the electrodes from decreasing depending on the charge / discharge state, thereby preventing a decrease in battery capacity.

[0016] Furthermore, according to the secondary battery of embodiment 1, the Li ions in the negative electrode layer are accelerated by the magnetic field, improving the liquid phase diffusion rate and promoting the diffusion of Li ions retained on the negative electrode surface, thereby improving rapid charging performance.

[0017] Furthermore, according to the secondary battery of the first embodiment, the diffusion of Li ions in the positive electrode layer is improved, and therefore, improvement in discharge characteristics is also expected.

[0018] The present disclosure is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present disclosure. For example, positive and negative active materials may be applied to both sides of the same foil. FIG. 3 is a cross-sectional view showing the schematic configuration of a secondary battery according to another embodiment. In FIG. 3, a negative electrode 302 is provided on a first main surface 311 of a foil 301. A positive electrode 303 is provided on a second main surface 312 of the foil 301.

[0019] In this way, it can be applied to a secondary battery with a bipolar electrode. The foil 301 may be a clad material.

[0020] The present invention may also be applied to sodium ion secondary batteries. [Explanation of symbols]

[0021] 100 Secondary battery 101 Positive electrode layer 102 negative electrode layer 103 Separator 104 Magnetic field generating means 110 battery cells 121 Foil 122 Negative electrode active material 301 Foil 302 negative electrode 303 Positive electrode

Claims

[Claim 1] a pair of a positive electrode layer and a negative electrode layer; a magnetic field generating means provided outside the positive electrode layer and the negative electrode layer, for generating a magnetic field in a predetermined direction in the positive electrode layer and the negative electrode layer.

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