JP2021177454A - Sealed battery - Google Patents

Abstract

To provide a technique capable of preventing energization between an electrode body and a battery case in flooding of a battery, thereby capable of ensuring excellent safety.SOLUTION: In a sealed battery 1 disclosed herein, an electrode body 20 and a nonaqueous electrolyte 30 are sealed at the inside of a battery case 10. The sealed battery 1 includes an electrode terminal 40 having a collector plate 45 connected to the electrode body 20 at one end, and an insulation container 50 made of a resin film, the insulation container accommodating the electrode body 20 and the nonaqueous electrolyte 30 therein. In the sealed battery 1 disclosed herein, a film welded part W1 where the resin films are welded together and a terminal welded part W2 where the resin film is welded to the surface of the collector plate 45 are formed in the insulation container 50, and the inside of the insulation container 50 is sealed. Thus, even if a conductive liquid enters the inside of the battery case 10, the conductive liquid can be prevented from contacting with the electrode body and the nonaqueous electrolyte, so that energization between the electrode body 20 and the battery case 10 in flooding of the battery can be prevented.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sealed battery. More specifically, the present invention relates to a sealed battery in which an electrode body and a non-aqueous electrolytic solution are sealed inside a metal battery case.

In recent years, non-aqueous electrolyte secondary batteries (hereinafter, also referred to as "secondary batteries") such as lithium ion secondary batteries and nickel-metal hydride batteries have been widely used as power sources for various devices. As an example of the use of such a secondary battery, a vehicle drive power source used for an electric vehicle (EV), a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), etc., a portable power source used for a laptop computer, a mobile terminal, etc. Power supply etc. can be mentioned. This type of secondary battery is configured by, for example, accommodating an electrode body and a non-aqueous electrolytic solution inside an exterior body. Examples of the exterior body of such a secondary battery include a metal battery case and a laminated exterior body made of a laminated film.

In general, since the laminated outer body is lightweight, it is considered that a secondary battery (laminated battery) using the laminated outer body is excellent in output characteristics per unit weight. Patent Document 1 discloses an example of a technique in which this type of laminated battery is used as a power source for driving a vehicle. Further, when such a laminated battery is used as a power source for driving a vehicle, a plurality of electrically connected laminated batteries (combined batteries) are used as various electronic components in order to protect the vehicle from impact and vibration during running. It is also required to be housed inside the pack case.

On the other hand, the metal battery case is superior in durability (impact resistance, scratch resistance, etc.) to the laminated exterior body. Therefore, the sealed battery in which the electrode body and the non-aqueous electrolytic solution are sealed inside the metal battery case can ensure excellent safety against impact and vibration during vehicle running. In this type of sealed battery, an insulating member is arranged between the electrode body and the battery case in order to prevent the metal battery case and the electrode body from being energized.

Patent Document 2 discloses an example of a sealed battery in which an insulating member is arranged between the electrode body and the battery case. In the sealed battery described in Patent Document 2, the electrode body is housed inside the insulating film formed in a box shape. Then, in this insulating film, a region forming an upper surface opening facing the upper surface (cover body) of the battery case is extended, and a part of the upper surface opening is extended so as to cover the electrode body by bending the extended portion. It's blocking. This makes it possible to prevent damage to the electrode body due to the intrusion of foreign matter (metal pieces, etc.) into the insulating film.

Japanese Unexamined Patent Publication No. 2016-139522 Japanese Unexamined Patent Publication No. 2019-110036

By the way, with the spread of secondary batteries in recent years, even better safety is required for sealed batteries that use a battery case. For example, since the power source for driving a vehicle is basically used outdoors, it may be flooded depending on the driving environment of the vehicle or a natural disaster. In this case, if a liquid having high electrical conductivity (hereinafter, also referred to as "conductive liquid") such as seawater enters the inside of the battery case, the battery case and the electrode body may be energized through the conductive liquid. There is.

The present invention has been made in view of such circumstances, and an object of the present invention is to prevent energization between the electrode body and the battery case when the battery is flooded in a sealed battery using a metal battery case, which is excellent. It is to provide technology that can ensure safety.

In order to solve the above-mentioned problems, a non-aqueous electrolyte secondary battery having the following configuration is provided.

In the sealed battery disclosed herein, the electrode body and the non-aqueous electrolytic solution are sealed inside a metal battery case in which the case body and the lid body are welded together. Such a sealed battery has an electrode terminal having a flat plate-shaped current collecting plate connected to the electrode body at one end and an external terminal exposed to the outside of the battery case at the other end, and an electrode body. It is provided with an insulating container made of a resin film that houses the non-aqueous electrolytic solution and insulates the electrode body and the battery case, and the current collector plate of the electrode terminal penetrates the insulating container. Then, in the sealed battery disclosed here, a film welded portion in which the resin films are welded to each other and a terminal welded portion in which the resin film is welded to the surface of the current collector are formed in the insulating container, and the insulating container is formed. The inside is sealed.

In the sealed battery having the above configuration, the electrode body and the non-aqueous electrolytic solution are sealed inside an insulating container made of a resin film. Therefore, even if the sealed battery is flooded and the conductive liquid invades the inside of the case, it is possible to prevent the conductive liquid from coming into contact with the electrode body or the non-aqueous electrolyte liquid. This makes it possible to reliably prevent energization between the electrode body and the battery case when the battery is flooded, and to provide a sealed battery having excellent safety.

It is a partial cross-sectional view which shows typically the internal structure of the closed type battery which concerns on one Embodiment. It is a partial cross-sectional view which shows the terminal connection process in the method of manufacturing the closed type battery shown in FIG. It is a partial cross-sectional view which shows the accommodating process in the method of manufacturing the closed type battery shown in FIG. It is a partial cross-sectional view which shows the welding process in the method of manufacturing the closed type battery shown in FIG. It is a partial cross-sectional view which shows the assembly manufacturing process in the method of manufacturing the closed type battery shown in FIG. It is a partial cross-sectional view which shows the liquid injection process in the method of manufacturing the closed type battery shown in FIG.

Hereinafter, an embodiment of the sealed battery disclosed herein will be described with reference to the drawings. It should be noted that matters other than those specifically mentioned in the present specification, which are necessary for carrying out the technology disclosed herein (for example, materials for an electrode body and a non-aqueous electrolyte solution, etc.), are in the art. It can be grasped based on the prior art. That is, the technology disclosed herein can be implemented based on the contents specified in the present specification and the common general technical knowledge in the field. The following embodiments are not intended to limit the techniques disclosed herein. Further, in the drawings shown in the present specification, members / parts having the same action are described with the same reference numerals. Furthermore, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect the actual dimensional relationships.

1. 1. Structure of Sealed Battery FIG. 1 is a partial cross-sectional view schematically showing the internal structure of the sealed battery according to the present embodiment. In each of the figures shown in the present specification, reference numeral X indicates "width direction (of the sealed battery)", and reference numeral Z indicates "height direction (of the sealed battery)". However, these directions are defined for convenience of explanation, and are not intended to limit the installation mode when the sealed battery disclosed herein is used.

(1) Overall Configuration The sealed battery 1 according to the present embodiment is constructed by sealing the electrode body 20 and the non-aqueous electrolytic solution 30 inside the battery case 10. Further, the sealed battery 1 includes an electrode terminal 40 and an insulating container 50 in addition to the above configuration. Hereinafter, each configuration will be described.

(2) Battery Case The battery case 10 shown in FIG. 1 is a square container having an internal space 10a, and the electrode body 20 and the non-aqueous electrolytic solution 30 are housed in the internal space 10a. The battery case 10 includes a box-shaped case body 12 having an open upper surface and a plate-shaped lid 14. The battery case 10 is constructed by closing the upper surface opening of the case body 12 with a lid body 14 and welding the case body 12 and the lid body 14. The battery case 10 (that is, the case body 12 and the lid 14) is made of a metal material having excellent durability such as impact resistance and scratch resistance. As the constituent material of the battery case 10, a conventionally known metal material can be used without particular limitation, but aluminum, an aluminum alloy, or the like is preferable in consideration of cost, weight, thermal conductivity, and the like.

Further, the lid body 14 is provided with a liquid injection port 16 for injecting the non-aqueous electrolytic solution 30, and the liquid injection port 16 is sealed by a sealing plug 18. As will be described in detail later, the battery case is formed by injecting the non-aqueous electrolytic solution 30 into the battery case 10 in which the case body 12 and the lid 14 are welded, and then sealing the injection port 16 with a sealing plug 18. The inside of 10 is sealed.

(3) Electrode body In the technique disclosed herein, the electrode body is not particularly limited, and a conventionally known structure can be adopted without particular limitation. For example, the electrode body 20 shown in FIG. 1 is a wound electrode body. The electrode body 20 is formed by winding a laminated body in which a long positive electrode and a long negative electrode are overlapped with each other via a separator. Further, a core portion 20a, which is a main field of the charge / discharge reaction, is formed in the central portion of the electrode body 20 in the width direction X. In the core portion 20a, the electrode active material layers of the positive electrode and the negative electrode are wound so as to face each other. On the other hand, terminal connection portions 20b and 20c connected to the current collector plate 45 of the electrode terminal 40 are formed at both ends of the electrode body 20 in the width direction X. In the terminal connection portions 20b and 20c, the current collecting foil of either the positive electrode or the negative electrode is wound in a state of protruding from the core portion 20a. For each member (positive electrode, negative electrode, separator, etc.) constituting the electrode body 20, a material that can be used for a conventionally known non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) can be used without particular limitation. , Since the technique disclosed herein is not limited, detailed description thereof will be omitted.

(4) Non-aqueous electrolytic solution The non-aqueous electrolytic solution 30 is prepared by dissolving a supporting salt in a non-aqueous solvent. A part of the non-aqueous electrolytic solution 30 permeates the inside of the electrode body 20 (between the electrodes of the positive electrode and the negative electrode). It is not necessary that all of the non-aqueous electrolytic solution 30 permeates the inside of the electrode body 20, and as shown in FIG. 1, a part of the non-aqueous electrolytic solution 30 is used as the surplus electrolytic solution 32 to the outside of the electrode body 20. It may exist. By providing such a surplus electrolytic solution 32, when the non-aqueous electrolytic solution 30 inside the electrode body 20 is insufficient, the surplus electrolytic solution 32 can be permeated into the inside of the electrode body 20. Similar to the electrode body 20, as the material of the non-aqueous electrolytic solution 30, any material that can be used in a conventionally known non-aqueous electrolytic solution secondary battery can be used without particular limitation, and the techniques disclosed herein are limited. Since it is not a thing, detailed description will be omitted.

(5) Electrode Terminals In the sealed battery 1 according to the present embodiment, a pair of electrode terminals 40 are attached to the battery case 10 (cover body 14). One of these electrode terminals 40 is connected to the positive electrode body 20 and functions as a positive electrode terminal, and the other is connected to a negative electrode and functions as a negative electrode terminal. Each electrode terminal 40 is a long conductive member extending along the height direction Z. At one end of these electrode terminals 40, a flat plate-shaped current collector plate 45 connected to the electrode body 20 (typically, terminal connection portions 20b and 20c) is formed. The current collector plate 45 penetrates the insulating container 50 described later and extends to the lower surface of the lid body 14. Further, an external terminal 47 exposed to the outside of the battery case 10 is formed at the other end of the electrode terminal 40. By connecting the external terminal 47 to an external device (motor, other secondary battery, etc.), the electrode body 20 in the battery case 10 and the external device can be electrically connected. As for the material of the electrode terminal 40, those that can be used in a conventionally known non-aqueous electrolytic solution secondary battery can be used without particular limitation, and the techniques disclosed herein are not limited, so detailed description thereof will be omitted. do.

(6) Insulated Container The insulated container 50 in the present embodiment is a bag-shaped member made of a resin film. In the sealed battery 1, the electrode body 20 and the non-aqueous electrolytic solution 30 are housed inside the insulating container 50. This makes it possible to prevent the battery case 10 and the electrode body 20 from being energized. As the resin film constituting the insulating container 50, an insulating resin material that is insoluble in the non-aqueous electrolyte solution 30 and can be heat-welded is used. Further, from the viewpoint of preventing deterioration of the airtightness due to breakage of the film, it is preferable that the film has a certain strength or higher. Examples of such a resin material include polypropylene (PP), polyethylene (PE), polychlorotrifluoroethylene, polyamide, polyester and the like.

In the present embodiment, the film welded portion W1 in which the resin films are welded to each other and the terminal welded portion W2 in which the resin film is welded to the surface of the current collector plate 45 are formed on the upper end portion of the insulating container 50 in the height direction Z. The electrode body 20 and the non-aqueous electrolytic solution 30 are sealed inside the insulating container 50. As a result, even if the sealed battery 1 is flooded and a conductive liquid such as seawater invades the internal space 10a of the battery case 10, the conductive liquid is prevented from coming into contact with the electrode body 20 and the non-aqueous electrolyte liquid 30. However, it is possible to prevent the electrode body 20 and the battery case 10 from being energized. Therefore, the sealed battery 1 according to the present embodiment has a very excellent safety that the electrode body 20 and the battery case 10 are not energized even when the battery 1 is submerged due to a natural disaster or the like.

Further, in the sealed battery 1 according to the present embodiment, the insulating container 50 is housed inside the sealed battery case 10. As a result, deterioration of the resin film constituting the insulating container 50 with time can be suppressed. Therefore, the sealed battery 1 according to the present embodiment can maintain excellent safety for a long period of time as compared with the sealed battery in which the outside of the battery case is covered with a resin material as a measure against flooding.

From the viewpoint of preventing deterioration of the sealing property due to breakage, the thickness of the resin film constituting the insulating container 50 is preferably 80 μm or more, preferably 85 μm or more, preferably 90 μm or more, and particularly preferably 95 μm or more. On the other hand, if the resin film becomes too thick, the electrode body 20 that can be accommodated in the battery case 10 becomes small, which causes a decrease in performance. From this point of view, the upper limit of the thickness of the resin film is preferably 150 μm or less, more preferably 145 μm or less, further preferably 140 μm or less, and particularly preferably 135 μm or less.

Further, in the insulating container 50 of the present embodiment, a liquid injection sealing portion 54 projecting toward the liquid injection port 16 is provided in a region of the lid 14 facing the liquid injection port 16. As will be described in detail later, by forming the liquid injection sealing portion 54, the film welding portion W1 can be easily formed after the injection of the non-aqueous electrolytic solution 30, and the insulating container 50 can be appropriately sealed.

2. Manufacture of Sealed Battery Next, a method of manufacturing the sealed battery 1 shown in FIG. 1 will be described. Such a manufacturing method includes a terminal connecting step, a housing step, a welding step, an assembly manufacturing step, a liquid injection step, and a sealing step. 2 to 6 are partial cross-sectional views showing each step in the method for manufacturing the sealed battery shown in FIG. 1. Hereinafter, each step will be described.

(1) Terminal connection step In this step, the electrode body 20 and the electrode terminal 40 are connected. Specifically, as shown in FIG. 2, electrode terminals 40 are attached to each of both ends of the lid 14 in which the liquid injection port 16 is opened in the width direction X. Then, the current collector plates 45 of the pair of electrode terminals 40 are joined to the terminal connection portions 20b and 20c of the electrode body 20. For the bonding process at this time, for example, ultrasonic welding or resistance welding is used.

(2) Containment Step As shown in FIG. 3, in this step, the electrode body 20 is accommodated inside the insulating container 50, and the liquid injection tube P is inserted into the liquid injection port 16 (see FIG. 2) of the lid body 14. do. Specifically, a bag-shaped insulating container 50 having an opening 52 formed on the upper surface is used, and the electrode body 20 is inserted into the insulating container 50 through the opening 52. As a result, the electrode body 20 is housed in the insulating container 50, and the opening 52 of the insulating container 50 and the lid body 14 face each other. Then, a heat-resistant (for example, metal) liquid injection tube P is inserted into the liquid injection port 16 from above the lid 14. As a result, the tip of the liquid injection pipe P is arranged inside the insulating container 50. As described above, in the present embodiment, the insulating container 50 having the convex liquid injection sealing portion 54 is used. In such a case, the positions of the insulating container 50 and the liquid injection pipe P are adjusted so that the liquid injection sealing portion 54 and the liquid injection pipe P overlap each other.

(3) Welding Step As shown in FIG. 4, in this step, the upper end portion of the insulating container 50 is welded except for the region where the liquid injection pipe P is arranged. Specifically, the upper end portion of the insulating container 50 is sandwiched between the pair of welding plates WP and heated while applying pressure. When the upper end portion of the insulating container 50 is heated and pressurized by the pair of welding plates WP in this way, the film welding portion W1 (see FIG. 1) is formed at the portion where the resin films face each other, and the facing resin films are formed. The terminal welded portion W2 is formed at a position where the current collecting plate 45 is interposed between the two. The welding plate WP faces each other so as to sandwich the upper end of the insulating container 50, but for convenience of explanation, the welding plate on the front side of the paper surface is omitted in FIG. 4, and only the welding plate WP on the back side of the paper surface is shown. doing. The omitted welding plate on the front side of the paper surface also has the same shape as the welding plate WP on the back side of the paper surface. Further, in the present embodiment, in order to prevent the resin film from welding to the surface of the injection pipe P, a recess WP1 for preventing interference between the injection pipe P and the welding plate WP is formed in the welding plate WP. Has been done.

(4) Assembly manufacturing process As shown in FIG. 5, in this process, the electrode body 20 covered with the insulating container 50 is housed in the case body 12, and the case body 12 and the lid body 14 are welded to form a battery. Build the assembly 100. Specifically, the electrode body 20 is inserted into the internal space 10a from the upper surface opening of the box-shaped case body 12, and the upper surface opening of the case body 12 is closed with the lid body 14. Then, the boundary portion between the case body 12 and the lid 14 is welded by using laser welding or the like. As a result, the battery assembly 100 in which the electrode body 20 is housed in the battery case 10 can be constructed. The term "battery assembly" as used herein refers to a sealed battery before the liquid injection port is sealed and the internal space is sealed.

(5) Liquid injection process As shown in FIG. 6, in this step, the non-aqueous electrolytic solution 30 is injected into the inside of the insulating container 50 via the liquid injection pipe P. Specifically, in this step, first, the liquid injection pipe P is connected to the decompression device to depressurize the inside of the insulating container 50. It is preferable that the pressure inside the insulating container 50 after depressurization is appropriately adjusted according to the internal capacity of the electrode body. Next, the liquid injection pipe P is connected to the liquid injection device, the non-aqueous electrolytic solution 30 is injected into the inside of the insulating container 50, and then the non-aqueous electrolytic solution 30 is held for a predetermined time. As a result, the non-aqueous electrolytic solution 30 can be efficiently permeated into the decompressed electrode body 20.

(6) Sealing Step In this step, the liquid injection pipe P is pulled out from the liquid injection port 16, the resin film in the unwelded portion where the liquid injection pipe P is inserted is welded, and then the liquid injection port is inserted with the sealing plug 18. 16 is sealed. As a result, the sealed battery 1 having the structure shown in FIG. 1 is constructed. When the insulating container 50 having the liquid injection sealing portion 54 is used as in the present embodiment, the convex liquid injection sealing portion 54 can be pulled out from the liquid injection port 16 to the outside of the battery case 10. Therefore, the liquid injection sealing portion 54, which is the unwelded portion into which the liquid injection pipe P has been inserted, can be easily welded to form the film welded portion W1.

3. 3. Other Embodiments Above, one embodiment of the technique disclosed herein has been described. It should be noted that the above-described embodiment shows an example to which the technology disclosed herein is applied, and does not limit the technology disclosed herein.

For example, in the above-described embodiment, a wound electrode body is used as the electrode body. However, the structure of the electrode body is not particularly limited, and a structure other than the wound electrode body can be adopted. Another example of such an electrode body is a laminated electrode body in which a plurality of positive electrodes and negative electrodes are sequentially laminated with a separator interposed therebetween.

Further, in the above-described embodiment, the bag-shaped insulating container 50 is used, and the inside of the container is sealed by welding the opening 52 at the upper end thereof. However, the shape of the insulated container is not limited to the above-described embodiment. For example, the electrode body can be accommodated inside the insulating container 50 by using a pair of resin films and welding the peripheral edge portion excluding the upper end portion in the accommodating step.

Although the present invention has been described in detail above, the above description is merely an example. That is, the techniques disclosed here include various modifications and modifications of the above-mentioned specific examples.

1 Sealed battery 10 Battery case 10a Internal empty can 12 Case body 14 Lid body 16 Liquid injection port 18 Sealing plug 20 Electrode body 20a Core part 20b, 20c Terminal connection part 30 Non-aqueous electrolytic solution 32 Surplus electrolytic solution 40 Electrode terminal 45 Current collector plate 47 External terminal 50 Insulated container 52 Opening 54 Liquid injection sealing part 100 Battery assembly

Claims (1)

A sealed battery in which an electrode body and a non-aqueous electrolyte solution are sealed inside a metal battery case in which the case body and the lid body are welded together.
An electrode terminal having a flat plate-shaped current collector plate connected to the electrode body at one end and an external terminal exposed to the outside of the battery case at the other end.
An insulating container made of a resin film that houses the electrode body and the non-aqueous electrolytic solution and insulates the electrode body and the battery case is provided.
The current collector plate of the electrode terminal penetrates the insulating container.
A film welded portion in which the resin films are welded to each other and a terminal welded portion in which the resin film is welded are formed on the surface of the current collector plate in the insulating container, and the inside of the insulating container is sealed. Molded battery.

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