Secondary battery

Abstract

The utility model relates to a secondary battery, which comprises: a winding body; an electrolyte; a shell, accommodating the winding body and the electrolyte; and a support portion, arranged at the lower part of the shell, supporting the curved part of the winding body, wherein the support portion is formed by a component that allows the electrolyte to pass through. Thus, the arc portion of the lower part of the winding body can be supported by the support portion that allows the electrolyte to pass through, and the reduction of battery performance can be suppressed.

Description

Technical Field

[0001] The utility model relates to a secondary battery. Background Art

[0002] In recent years, secondary batteries having a wound body and an electrolyte solution housed in a case have been used. Patent Document 1 describes that a support portion is provided to abut against a bent portion of a wound body to prevent the wound body from being damaged by contact with the support portion.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-168283

[0004] The lithium precipitation resistance of a secondary battery affects the battery performance and safety of the secondary battery. In a secondary battery, lithium is easily precipitated due to the loosening or deterioration of the winding body, and the battery performance is reduced due to the lithium precipitation. Therefore, it is hoped that the battery performance of the secondary battery can be suppressed by achieving a state in which lithium is difficult to precipitate.

[0005] In the secondary battery disclosed in Patent Document 1, since the support portion is provided to abut against the bent portion of the winding body, the electrolyte contained in the case may not be in contact with the winding body. If the electrolyte cannot fully contact the winding body, the battery performance may be reduced. Utility Model Content

[0006] The utility model provides a secondary battery which suppresses the reduction of battery performance.

[0007] The secondary battery of the utility model comprises: a winding body; an electrolyte; a shell for accommodating the winding body and the electrolyte; and a support portion arranged at the lower part of the shell for supporting the curved portion of the winding body, wherein the support portion is formed by a member that allows the electrolyte to penetrate.

[0008] Thereby, the arc portion of the lower part of the wound body can be supported by the support portion that allows the electrolyte to permeate.

[0009] According to the present invention, a secondary battery in which a decrease in battery performance is suppressed can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view showing an example of the external appearance of a secondary battery according to one embodiment.

[0011] Figure 2 It is a cross-sectional view showing the interior of a secondary battery according to one embodiment.

[0012] Figure 3 It is a cross-sectional view showing the interior of a secondary battery according to one embodiment.

[0013] Figure 4This is a diagram showing an example of a lithium deposition process in a secondary battery according to an embodiment. DETAILED DESCRIPTION

[0014] Hereinafter, a secondary battery according to one embodiment will be described with reference to the drawings. Figure 1 : is a diagram showing an example of the appearance of a secondary battery. Figure 2 To express Figure 1 FIG. 1 is a diagram showing an example of a cross section at a location indicated by a dotted line.

[0015] like Figure 1 and Figure 2 As shown, the secondary battery 1 includes a case 11 , a winding body 12 accommodated in the case 11 , an electrolyte 13 , and a support portion 14 .

[0016] like Figure 1 As shown, the case 11 is substantially in the shape of a rectangular parallelepiped and has a space therein capable of accommodating the wound body 12 , the electrolyte 13 , and the support portion 14 .

[0017] like Figure 2 As shown, the wound body 12 is an electrode body whose upper and lower parts are formed in an arc shape. The curved parts formed in the upper and lower parts, that is, the arc-shaped parts are arc parts 12a. Figure 3 For Figure 2 The cross-sectional view is a view specifically showing a state in which the wound body 12 is formed by a plurality of electrodes 21 in the inner and outer directions, and shows a state in which the arc portion 12a is supported by the support portion 14. Figure 3 In the figure, the housing 11 and the electrolyte 13 are omitted for easy understanding.

[0018] Here, the electrodes 21 may be loose at the arc portion 12a of the wound body 12. Specifically, the loosening between the electrodes 21 in the initial stage of forming the wound body 12 may be caused by winding loosening, and the loosening between the electrodes 21 after the initial stage may be caused by gas stagnation or the like.

[0019] The electrolyte 13 is a liquid contained in the case 11 in a state of being in contact with the wound body 12. In the secondary battery 1, the electrolyte 13 is in sufficient contact with the wound body 12, so that the secondary battery 1 can function as a battery.

[0020] The support portion 14 is disposed inside the housing 11 and on the lower surface 11a. More specifically, the support portion 14 is disposed between the lower surface 11a of the housing 11 and the arc portion 12a of the winding body 12, and abuts against both. The support portion 14 is a resin mesh sheet, preferably polypropylene (PP) or polyphenylene sulfide (PPS) having resistance to the electrolyte 13, but the material is not limited to these, as long as it is a member that allows the electrolyte 13 to pass through.

[0021] Here, in order to explain the effect of using the resin mesh sheet as the support portion 14 to support the arc portion 12a of the wound body 12, refer to Figure 4 (a) to (e) illustrate an example of a state in which the electrodes 21 of the curved portion 12 a of the wound body 12 are relaxed, that is, a process in which lithium (Li) is deposited in the curved portion 12 a of the wound body 12 .

[0022] like Figure 4 As shown in (a), in the early stage of forming the wound body 12, the distance between the electrodes 21 has a distribution with a certain deviation, especially in the arc portion 12a.

[0023] like Figure 4 As shown in (b), when the wound body 12 is placed in the electrolyte 13, gas accumulation occurs in the pocket portion where the distance difference occurs between the electrodes 21 of the wound body 12. That is, bubbles accumulate in a portion of the space between the electrodes 21 forming the wound body 12.

[0024] When from this Figure 4 When the power is turned on in the state shown in (b), Figure 4 As shown in (c), Li is precipitated at the contours of the bubbles retained in the wound body 12 .

[0025] Afterwards, if Figure 4 As shown in (d), even when the bubbles are separated from the electrodes 21 of the wound body 12, the distance distribution between the electrodes 21 is changed in the pocket where the bubbles were retained. That is, in the wound body 12, a portion where the distance between the electrodes 21 is shorter is generated, and electric power is easily concentrated in the portion where the distance between the electrodes 21 is shorter.

[0026] After that, if Figure 4 As shown in (e), Figure 4 In (c), new Li precipitates between the Li precipitated at the location of the bubble outline.

[0027] In order to suppress the Li deposition in the secondary battery 1 that occurs in this way, the following aspects are effective.

[0028] like Figure 4 As shown in (a), in particular, in the arc portion 12a of the wound body 12, pockets are generated due to the deviation in the distance distribution between the electrodes 21, and gas stagnation occurs. Therefore, it is effective to reduce the deviation by supporting the arc portion 12a of the wound body 12.

[0029] Therefore, in Figure 4In the initial stage of forming the secondary battery 1 shown in (a), the support portion 14 supports the arc portion 12a of the winding body 12 from below while being sandwiched between the lower surface 11a of the case 11 and the arc portion 12a of the winding body 12. As a result, the electrode 21 of the arc portion 12a of the winding body 12 is held by an external force, and the occurrence of spreading between the electrodes 21 is suppressed.

[0030] And, even in Figure 4 When the secondary battery 1 shown in (e) deteriorates, the support portion 14 can support the arc portion 12a of the wound body 12 with external force to suppress the separation of the electrodes 21 caused by gas generation. Therefore, Li deposition caused by the distance difference between the electrodes 21 of the wound body 12 can be suppressed.

[0031] Furthermore, since the support portion 14 is made of a resin mesh sheet that easily allows the electrolyte to permeate, the curved portion 12a of the wound body 12 is easily in contact with the electrolyte 13. Therefore, in the secondary battery 1, a decrease in battery performance due to the provision of the support portion 14 can be suppressed.

[0032] In addition, the present invention is not limited to the above-mentioned embodiments, and can be appropriately changed within the scope of the main purpose. That is, in order to clearly explain, the above-mentioned records are appropriately omitted and simplified, and those skilled in the art can easily change, add, and transform each element of the embodiment within the scope of the present invention.

Claims

1. A secondary battery, characterized in that: have: winding body; Electrolyte; A shell, accommodating the winding body and the electrolyte; and The support portion is disposed at a lower portion of the case and supports the bent portion of the wound body, wherein the support portion is formed of a member that allows the electrolyte to penetrate.

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