US-12620629-B2 - Battery cell and manufacturing method of the same

Abstract

A battery cell capable of holding an electrode laminate uniformly and improving lamination dislocation as well as the durability of an electrode is provided. A battery cell includes an electrode laminate in which a positive electrode and a negative electrode are alternately laminated via an electrolyte layer. The battery cell includes a tube-shaped insulating member that holds the electrode laminate, and the insulating member is heat-shrinkable mainly in a direction parallel to the lamination direction of the electrode laminate. The insulating member preferably has a heat shrinkage percentage of to −5% to 5% in a direction in which the current collector tab of the electrode laminate extends.

Inventors

• Masahiro Ohta
• Kosei MIYATA
• Yohei NOJI

Assignees

• HONDA MOTOR CO., LTD.

Dates

Publication Date

20260505

Application Date

20220221

Priority Date

20210330

Claims (5)

1. 1 . A manufacturing method of a battery cell having an electrode laminate in which a positive electrode and a negative electrode are alternately laminated via an electrolyte layer, the manufacturing method comprising: a first heating step of heating then heat shrinking a surface of an insulating member that is tube-shaped and heat-shrinkable, the surface being disposed on an electrode surface side of the electrode laminate; arranging the electrode laminate into an internal space of the insulating member such that a heat shrinked surface is the electrode surface side of the electrode laminate; and after the arranging, a second heating step of heat-shrinking a surface of the insulating member disposed on a laminate surface side of the electrode laminate by heating.
2. 2 . The manufacturing method of a battery cell according to claim 1 , wherein the heating temperature in the second heating step is 60° C. or higher.
3. 3 . The manufacturing method of a battery cell according to claim 1 , wherein at least any one of heating temperature in the second heating step and the heating temperature for previously heating the surface disposed on the electrode surface side of the electrode laminate of the insulating member is 60° C. or higher.
4. 4 . The manufacturing method of a battery cell according to claim 1 , further comprising a drawing portion forming step comprising forming a drawing portion after heating both end parts in the extending direction of the current collector tab of the electrode laminate of the insulating member.
5. 5 . The manufacturing method of a battery cell according to claim 4 , wherein the drawing portion forming step comprises a first drawing portion forming step comprising heating one end part in the extending direction of the current collector tab of the electrode laminate of the insulating member, and a second drawing portion forming step comprising heating the other end part in the extending direction of the current collector tab of the electrode laminate of the insulating member, and wherein the arranging step is carried out between the first drawing portion forming step and the second drawing portion forming step.

Description

This application is based on and claim the benefit of priority from Japanese Patent Application No. 2021-056433, filed on 30 Mar. 2021, the content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a battery cell and a manufacturing method of the battery cell. Related Art A secondary battery such as a lithium-ion secondary battery has conventionally been in widespread use, as a secondary battery having a high energy density. A liquid secondary battery has a separator disposed between a positive electrode and a negative electrode and includes a cell structure filled with a liquid electrolyte (electrolytic solution). Furthermore, in the case of an all-solid-state battery where the electrolyte is a solid, the battery includes a cell structure in which a solid electrolyte is interposed between a positive electrode and a negative electrode. A secondary battery is constituted by a laminate formed by a plurality of the unit cells layered. These are all sealed and packaged using outer packages. As a cell structure of a secondary battery having the above laminate, for example, in a nonaqueous electrolyte secondary battery including a layered electrode body formed by laminating a positive electrode, a separator, and a negative electrode, one in which the laminated structure of a layered electrode body can be maintained through winding a porous sheet holding a nonaqueous electrolyte around the outer periphery of a layered electrode body, has been known (for example, see Patent Document 1). Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2014-093128 SUMMARY OF THE INVENTION With a secondary battery having the above-mentioned laminate, there is a problem in that lamination dislocation is caused between a positive electrode, a negative electrode, and a solid electrolyte. The technology disclosed by Patent Document 1 does not have enough force in holding a laminate. Therefore, there is a probability of lamination dislocation in winding a porous sheet around a laminate, in accommodating a laminate in an outer package, when an impact from the outside is applied or the like. Increasing the dimensional difference between a positive electrode and a negative electrode for preventing electrodeposition considering the possibility of lamination dislocation, lowers an energy density. In addition, when an attempt is made to hold a laminate by winding a sheet-shaped body around the laminate, a level difference arises at the winding end part. This results in stress distribution generated in the laminate as well as degradations of the initial performance find durability. There is also room for improvement with respect to the durability of the electrode itself. In order to address the above-mentioned problems, one possible way of suppressing lamination dislocation through holding the laminate is to insert a laminate into a tube-shaped heat shrinkable film and shrink the heat shrinkable film by heating. However, simply heating a heat shrinkable film in which a laminate is accommodated may lead to the ununiformed distance between electrodes or deformed electrodes due to a stress applied to the laminate surface of a laminate. To prevent the above event, for example, when only the laminate surface in a heat shrinkable film is shrunk by heating, the unheated surface of a heat shrinkable film being shrunk due to temperature rises in using a secondary battery or natural shrinkage may lead to the ununiformed distance between electrodes or deformed electrodes. The present Invention has been made in view of the above-mentioned problems. Additionally/the present invention has an object to provide a battery cell capable of holding an electrode laminate uniformly and improving lamination dislocation as well as the durability of an electrode. (1) The present invention relates to a battery cell including: an electrode laminate including positive and negative electrodes and an electrolyte layer/the positive and negative electrodes being alternately laminated with the electrolyte layer interposed between them; and a tube-shaped insulating member that holds the electrode laminate, wherein the insulating member is heat-shrinkable mainly in a direction parallel to the lamination direction of the electrode laminate.(2) The battery cell described in (1), wherein the insulating member has a heat shrinkage percentage of −5% to 5% in a direction in which a current collector tab of the electrode laminate extends.(3) The battery cell described in (1) or (2), wherein the insulating member has a heat shrinkage percentage of 5% to 80% in the lamination direction.(4) The battery cell described in any one of descriptions (1) to (3), wherein when heat-shrunk in the main direction, the insulating member has a thickness tv on an electrode surface side of the electrode laminate and has a thickness th on a laminate surface side of the electrode laminate, and the insul