JP5777093B2 - Secondary battery and method for manufacturing secondary battery - Google Patents

Description

  Embodiments described herein relate generally to a secondary battery and a method for manufacturing the secondary battery.

  In recent years, with the spread of portable electronic devices such as information terminal devices and notebook personal computers, and vehicles such as hybrid electric vehicles, the demand for secondary batteries used for their power sources is increasing. As such a secondary battery, for example, a battery having a casing in which a cap is joined to a metal can by welding or caulking, a battery using a laminate material for the casing, and the like have been developed (for example, Patent Document 1). reference).

JP 2008-71730 A

  However, when a cap is joined to a metal can by welding or caulking as described above, metal powder such as welding spatter and dust may be mixed in the casing during its production, so a complete insulation state must be formed. In many cases, electric corrosion occurs in the casing, and liquid leakage occurs from a welded portion.

  In addition, when a laminate material is used for the housing, the strength of the housing is insufficient, so that a crack may occur in the metal layer or the resin layer of the laminate material when the battery is fixed. For this reason, moisture permeation occurs due to cracks in the metal layer, insulation cannot be maintained due to micro cracks in the resin layer, etc., and electrolytic corrosion of the metal layer occurs, resulting in liquid leakage.

  The problem to be solved by the present invention is to provide a secondary battery and a method for manufacturing the secondary battery that can reliably prevent the occurrence of leakage of the electrolyte.

The secondary battery according to the embodiment includes a housing, an electrode body provided in the housing and having a positive electrode and a negative electrode, a positive electrode terminal provided in the housing and electrically connected to the positive electrode of the electrode body A negative electrode terminal provided in the housing and electrically connected to the negative electrode of the electrode body; an electrical connection between the positive electrode and the positive electrode terminal of the electrode body provided in the housing; and a negative electrode and a negative electrode of the electrode body Between the negative electrode terminal and the housing , a bag-like insulating sheet that encloses the electrode body together with the electrolyte, a positive seal material that seals between the positive electrode terminal and the housing, and an electrical connection with the terminal And an insulating sheet is welded to the positive electrode sealing material and the negative electrode sealing material . In addition, the secondary battery according to the embodiment includes a housing, an electrode body provided in the housing and having a positive electrode and a negative electrode, and a positive electrode provided in the housing and electrically connected to the positive electrode of the electrode body. A terminal, a negative electrode terminal provided in the housing and electrically connected to the negative electrode of the electrode body; an electrical connection between the positive electrode and the positive electrode terminal of the electrode body provided in the housing; and a negative electrode of the electrode body And a bag-like insulating sheet that encloses the electrode body together with the electrolyte solution, and the insulating sheet includes a positive electrode sealing portion that seals between the positive electrode terminal and the housing. And a negative electrode seal portion that seals between the negative electrode terminal and the housing.

The manufacturing method of the secondary battery according to the embodiment encloses the electrode body with an insulating sheet so that the positive electrode terminal and the negative electrode terminal provided on the lid body and the positive electrode and the negative electrode of the electrode body can be electrically connected to each other with the same polarity. A step of welding the peripheral edge of the insulating sheet enclosing the electrode body except a part thereof, forming an insulating sheet into a bag shape while forming a liquid injection port for injecting an electrolyte, and a bag-like shape A step of injecting an electrolyte solution into the insulating sheet from the injection port, a step of closing the injection port of the bag-like insulation sheet into which the electrolyte solution has been injected, and a bag-like insulation sheet with the injection port closed One end opening is provided in the container body, the opening of the container body is closed with a lid, the container body and the lid are joined, and before the electrode body is wrapped with the insulating sheet, the gap between the positive electrode terminal and the lid is With the positive electrode sealant, the gap between the negative electrode terminal and the lid is And a step of sealing, in the step of wrapping the electrode assembly by the insulating sheet, welding the insulating sheet as a positive electrode sealing material and the negative electrode sealing material.
In addition, the method for manufacturing a secondary battery according to the embodiment includes an insulating sheet for an electrode body so that the positive electrode terminal and the negative electrode terminal provided on the lid body and the positive electrode and the negative electrode of the electrode body can be electrically connected to each other with the same polarity. A step of enclosing the electrode body, a step of welding the peripheral edge of the insulating sheet enclosing the electrode body, excluding a part thereof, and forming an injection sheet for injecting an electrolytic solution, and forming the insulating sheet into a bag shape, and a bag A step of injecting an electrolytic solution into the interior of the liquid-like insulating sheet from the liquid inlet, a step of closing the liquid inlet of the bag-like insulating sheet into which the electrolytic solution has been injected, and a bag-shaped insulation in which the liquid inlet is closed The sheet is provided in the container body having an opening at one end, the opening of the container body is closed by the lid, the container body and the lid are joined, and the positive electrode seal portion is used as the insulation sheet before the electrode body is wrapped with the insulation sheet. And an insulating sheet having a negative electrode seal portion, The positive electrode seal portion between the terminal and the cover member, comprising the step of sealing the negative electrode seal portion between the negative electrode terminal and the lid.

It is sectional drawing which shows schematic structure of the secondary battery which concerns on one Embodiment. It is sectional drawing which expands and shows a part of secondary battery shown in FIG. It is a perspective view for demonstrating the manufacturing process of the secondary battery shown in FIG. FIG. 3 is a first front view for explaining a manufacturing process for the secondary battery shown in FIG. 1. FIG. 6 is a second front view for explaining a manufacturing process for the secondary battery shown in FIG. 1. It is sectional drawing which shows the modification 1 of the secondary battery shown in FIG. It is sectional drawing which shows the modification 2 of the secondary battery shown in FIG.

  An embodiment will be described with reference to the drawings.

  As shown in FIG. 1, the secondary battery 1 according to this embodiment includes a housing 2, an electrode body 3 provided in the housing 2, a pair of positive terminals 4 provided in the housing 2, and The negative electrode terminal 5, the positive electrode lead 6 that electrically connects the electrode body 3 and the positive electrode terminal 4, the negative electrode lead 7 that electrically connects the electrode body 3 and the negative electrode terminal 5, and the electrode body 3 together with the electrolyte And a bag-like insulating sheet 8 to be accommodated. Examples of the secondary battery 1 include a nonaqueous electrolyte secondary battery such as a lithium ion battery.

  The housing | casing 2 is a flat rectangular parallelepiped exterior container, for example, is formed with metal materials, such as aluminum or aluminum alloy. The housing 2 has a container body 2a having one end opening whose upper end (in FIG. 1) is open, and a rectangular plate-shaped lid 2b that closes the opening of the container body 2a. It is welded to the container body 2a to be formed airtight and liquid tight.

  For example, a rectangular pressure release valve 2b1 is provided at the center of the lid 2b. The pressure release valve 2b1 is formed by thinning a part of the lid 2b to a thickness of about half, and a stamp is formed at the center of the upper surface of the thin part. The pressure release valve 2b1 is opened when the gas is generated in the housing 2 due to the occurrence of an abnormality and the internal pressure of the housing 2 rises to a predetermined value or more, and the gas in the housing 2 is released. The internal pressure of 2 is lowered to prevent problems such as rupture of the secondary battery 1.

  In the electrode body 3, a positive electrode current collector (positive electrode) whose surface is coated with a positive electrode active material and a negative electrode current collector (negative electrode) whose surface is coated with a negative electrode active material are wound through a separator. It is formed in a flat shape. One end of the electrode body 3 in the winding axis direction functions as the positive electrode current collecting tab 3a, and the other functions as the negative electrode current collecting tab 3b. In addition, as the positive electrode current collector or the negative electrode current collector, for example, a metal foil or the like is used.

  The positive terminal 4 is provided at one end in the longitudinal direction of the lid 2b, and the negative terminal 5 is provided at the other end. The positive electrode terminal 4 and the negative electrode terminal 5 are arranged in the winding axis direction of the electrode body 3 with the pressure on / off valve 2b1 therebetween, and are formed of a conductive material such as metal. The positive electrode terminal 4 extends through the lid body 2b and the insulating sheet 8, is fixed to the positive electrode lead 6, and is electrically connected to the positive electrode of the electrode body 3, that is, the positive electrode current collecting tab 3a. Similarly, the negative electrode terminal 5 extends through the lid body 2b and the insulating sheet 8, and is fixed to the negative electrode lead 7 and electrically connected to the negative electrode of the electrode body 3, that is, the negative electrode current collecting tab 3b. Yes.

  Between the positive electrode terminal 4 and the lid 2b, there are provided a first frame 4a that is an insulator such as resin, and an insulator such as resin or glass, for example, a positive electrode sealing material 4b called a gasket. (See FIG. 2). Similarly, between the negative electrode terminal 5 and the lid 2b, there is a second frame 5a that is an insulator such as a resin, and an insulator such as a synthetic resin or glass, for example, a negative electrode seal material 5b called a gasket. Is provided. The first frame body 4a and the second frame body 5a are located on the upper surface of the lid body 2b, and electrically insulate the positive electrode terminal 4 and the negative electrode terminal 5 from the housing 2. Further, the positive electrode sealing material 4b and the negative electrode sealing material 5b are located between the positive electrode terminal 4 and the negative electrode terminal 5 penetrating the lid body 2b and the lid body 2b, and the positive electrode terminal 4 and the negative electrode terminal 5 and the housing 2 are located. Are hermetically and liquid tightly sealed and electrically insulated.

  The positive electrode lead 6 is formed of a conductive material such as metal, and is a lead portion that electrically connects the positive electrode current collecting tab 3 a of the electrode body 3 and the positive electrode terminal 4. The positive electrode lead 6 extends from the ceiling surface of the housing 2 along the side surface thereof, and is formed in a shape that sandwiches the positive electrode current collecting tab 3a from both sides. The end of the positive electrode lead 6 on the electrode body 3 side is fixed to the positive electrode current collecting tab 3a of the electrode body 3 by ultrasonic welding. A positive electrode terminal hole 6 a is formed at the end of the positive electrode lead 6 on the lid 2 b side, and the positive electrode terminal 4 is fitted into the positive electrode terminal hole 6 a and joined to the positive electrode lead 6.

  The negative electrode lead 7 is formed of a conductive material such as metal, and is a lead portion that electrically connects the negative electrode current collecting tab 3 b of the electrode body 3 and the negative electrode terminal 5. The negative electrode lead 7 extends from the ceiling surface of the housing 2 along the side surface thereof, and is formed in a shape that sandwiches the negative electrode current collecting tab 3b from both sides. The end of the negative electrode lead 7 on the electrode body 3 side is fixed to the negative electrode current collecting tab 3b of the electrode body 3 by ultrasonic welding. A negative electrode terminal hole 7 a is formed at the end of the negative electrode lead 7 on the lid 2 b side, and the negative electrode terminal 5 is fitted in the negative electrode terminal hole 7 a and joined to the negative electrode lead 7.

  The insulating sheet 8 enables electrical connection between the positive electrode of the electrode body 3 and the positive electrode terminal 4 and electrical connection between the negative electrode of the electrode body 3 and the negative electrode terminal 5. It is formed in a bag shape that wraps 7 together with the electrolytic solution. The bag-shaped insulating sheet 8 is housed inside the housing 2, and an electrolyte is injected into the bag-shaped insulating sheet 8. As the insulating sheet 8, a sheet having insulating properties and flexibility, for example, a film-like resin sheet is used. The thickness of this resin sheet is, for example, about 10 μm to 0.5 mm.

  This bag-shaped insulating sheet 8 has a positive electrode through hole 8a through which the positive electrode terminal 4 penetrates and a negative electrode through hole 8b through which the negative electrode terminal 5 penetrates. The connection between the positive electrode terminal 4 and the positive electrode lead 6 and the negative electrode The terminal 5 and the negative electrode lead 7 are connected to each other. The positive electrode terminal 4 passes through the lid body 2 b, passes through the positive electrode through hole 8 a, and is fitted in the positive electrode terminal hole 6 a of the positive electrode lead 6. Similarly, the negative electrode terminal 5 also passes through the lid body 2 b, passes through the negative electrode through hole 8 b, and is fitted in the negative electrode terminal hole 7 a of the negative electrode lead 7. The bag-like insulating sheet 8 is welded to the positive electrode sealing material 4b and the negative electrode sealing material 5b. Thereby, the liquid leakage of the electrolyte from between the insulating sheet 8 and the positive electrode sealing material 4b or between the insulating sheet 8 and the negative electrode sealing material 5b can be prevented.

  Furthermore, the bag-like insulating sheet 8 has an open portion 8c (dot pattern in FIG. 1) that is opened when the internal pressure of the bag body exceeds a predetermined value. The open portion 8c is opened to release gas in the bag-like insulating sheet 8 when gas is generated in the bag-like insulating sheet 8 due to occurrence of an abnormality and the internal pressure rises to a predetermined value or more. The internal pressure is lowered to prevent problems such as rupture of the insulating sheet 8. The gas released from the bag-like insulating sheet 8 accumulates in the housing 2. However, when the internal pressure of the housing 2 reaches a predetermined value, the pressure release valve 2b1 of the lid 2b is opened. , Released from there. At this time, the gas remaining in the bag-like insulating sheet 8 also flows from the opening 8c to the pressure release valve 2b1 through the passage between the housing 2 and the insulating sheet 8 and is released. Since the gas flow path is ensured between the housing 2 and the insulating sheet 8 in this way, smooth gas discharge can be realized.

  Such an open portion 8c is formed by partially weakening the welding force during manufacture for forming the insulating sheet 8 in a bag shape, or by thinning a part of the insulating sheet 8. The structure is not particularly limited as long as the internal pressure of the sheet-like insulating sheet 8 becomes an open state in response to the predetermined value or more. Further, since the gas flow path is secured, the position of the opening 8c may be any position on the bag-like insulating sheet 8. For example, in order to shorten the gas removal time, the pressure release valve 2b1 of the lid 2b is used. It may be a position opposite to.

  Next, the manufacturing process (manufacturing method) of the above-described secondary battery 1 will be described.

  The manufacturing process includes a step of wrapping the electrode body 3 with the insulating sheet 8 (see FIG. 3), and a portion other than the liquid injection port 11 on the periphery of the insulating sheet 8 wrapped in the bag shape. A welding step (see FIG. 4), a liquid injection step of injecting an electrolytic solution into the insulating sheet 8 after welding, and a closing step of closing the liquid injection port 11 of the insulating sheet 8 after the injection ( Finally, it has the joining process which assembles the housing | casing 2 and welds. The flow of this manufacturing process will be described in order.

  First, as shown in FIG. 3, the positive electrode terminal 4 and the negative electrode terminal 5 are penetrated and attached to the lid body 2b from the surface of the lid body 2b. At this time, the first frame 4a and the positive electrode sealing material 4b, and further the second frame 5a and the negative electrode sealing material 5b (both see FIG. 1) are also provided.

  Next, the rectangular insulating sheet 8 is bent in half, the rod portion of the positive electrode terminal 4 is passed through the positive electrode through hole 8a of the insulating sheet 8, the rod portion of the negative electrode terminal 5 is passed through the negative electrode through hole 8b, and the lid 2b. An insulating sheet 8 is attached to the back side of the sheet. In this state, the insulating sheet 8, the positive electrode sealing material 4b, and the negative electrode sealing material 5b are welded.

  Thereafter, the positive electrode lead 6 is inserted into the bent insulating sheet 8, and the positive electrode terminal hole 6 a of the positive electrode lead 6 and the rod portion of the positive electrode terminal 4 passing through the positive electrode through hole 8 a of the insulating sheet 8 are fitted. Match. Similarly, the negative electrode lead 7 is inserted into the bent insulating sheet 8, and the negative electrode terminal hole 7 a of the negative electrode lead 7 and the rod portion of the negative electrode terminal 5 that has passed through the negative electrode through hole 8 b of the insulating sheet 8 are connected. The positive electrode lead 6 and the negative electrode lead 7 are attached to the back surface side of the lid body 2b via the insulating sheet 8 by fitting.

  Next, the positive electrode current collecting tab 3a of the electrode body 3 is sandwiched by the positive electrode lead 6 attached to the back surface of the lid body 2b, and the negative electrode current collector of the electrode body 3 is further sandwiched by the negative electrode lead 7 attached to the back surface of the lid body 2b. The positive electrode lead 6, the negative electrode lead 7, and the electrode body 3 are fitted together so as to sandwich the tab 3b. In this state, the pair of leg portions of the positive electrode lead 6 are fixed to the positive electrode current collecting tab 3a by ultrasonic welding, and similarly, the pair of leg portions of the negative electrode lead 7 are fixed to the negative electrode current collecting tab 3b by ultrasonic welding. . Here, the positive electrode lead 6, the negative electrode lead 7, and the electrode body 3 are located inside the folded insulating sheet 8.

  Thereafter, as shown in FIG. 4, the insulating sheet 8 folded in half is welded except for a part thereof, and the insulating sheet 8 is formed in a bag shape while forming a liquid injection port 11 for injecting an electrolytic solution. To form. The insulating sheet 8 formed into a bag shape by this welding has a belt-like welded portion 12 (in FIG. 4) extending along the periphery of the insulating sheet 8 except for the portion of the pouring port 11 in addition to the pouring port 11. Dot pattern). Next, an electrolytic solution is injected into the bag-shaped insulating sheet 8 from the liquid injection port 11.

  After completion of the liquid injection, as shown in FIG. 5, the liquid injection port 11 of the insulating sheet 8 is welded and the liquid injection port 11 is closed. Thereby, the liquid injection port 11 is closed, and the bag-like insulating sheet 8 includes the belt-like welded portion 12 (including the dot pattern in FIG. 5) that extends along the periphery of the insulating sheet 8 including the portion of the liquid injection port 11. ). The welding portion 12 has a welding mark 13 in which the liquid injection port 11 is closed by welding. This welding mark 13 is a mark generated when the liquid injection port 11 is closed. For example, the welding mark 13 has double marks overlapping at both ends by welding that makes the insulating sheet 8 into a bag shape and welding that closes the liquid injection port 11. become. This double mark is a place where the process of melting and solidification is repeated twice. In the above-described welding of the liquid injection port 11, the liquid injection port 11 is welded and closed, and the welding trace 13 is an open portion 8 c that is opened when the internal pressure of the bag-like insulating sheet 8 exceeds a predetermined value. .

  Next, before inserting the above-mentioned bag-shaped insulating sheet 8 into the container body 2a, the welded portion 12 of the bag-shaped insulating sheet 8 is bent along lines L1 to L3. In addition, although the welding part 12 of the bag-shaped insulating sheet 8 may be cut | disconnected by the lines L1-L3, it can prevent that the direction which bent performs generation | occurrence | production of foreign materials, such as a cut piece and dust. However, if it is impossible or difficult to insert into the container body 2a even after bending, the welded portion 12 of the bag-like insulating sheet 8 is cut along lines L1 to L3. In this case, the welding part 12 will have a cutting trace (end part shown by the lines L1-L3).

  Thereafter, the welded portion 12 is bent or cut into a bag-like insulating sheet 8 (containing the electrode body 3, the positive electrode lead 6, the negative electrode lead 7, and the electrolyte therein) as a container body 2a (see FIG. 1), a coil press for suppressing swelling of the electrode body 3 is performed so that the electrode body 3 can be easily inserted. After the coil press, a compressed bag-like insulating sheet 8 is provided through the opening of the container main body 2a, and at the same time, the opening of the container main body 2a is closed by the lid 2b. Finally, the container main body 2a and the lid are closed. The body 2b is welded. Thereby, the secondary battery 1 as shown in FIG. 1 is completed.

  In such a manufacturing process, when the container body 2a and the lid 2b are welded, the electrode body 3 and the electrolytic solution are encased in the bag-like insulating sheet 8, so that welding spatter, dust, etc. It is possible to prevent the metal powder from being mixed into the electrode body 3 or the electrolytic solution. Moreover, since it injects from the injection hole 11 of the bag-shaped insulating sheet 8, and injects the injection hole 11 after the injection, it is necessary to form the injection hole in the lid 2b as usual. There is no need to perform welding for sealing the liquid injection port. Thereby, a manufacturing process can be simplified. Furthermore, since it is possible to wrap the electrolyte solution in the bag-like insulating sheet 8 and prevent the electrolyte solution from coming into direct contact with the housing 2, a crack or the like occurs in the housing 2 when the secondary battery 1 is used. However, it is possible to prevent the electrolyte from flowing out of the housing 2, and as a result, it is possible to prevent a short circuit due to the electrolyte. In addition, by using the bag-like insulating sheet 8, the positive electrode current collecting tab 3a, the negative electrode current collecting tab 3b, the positive electrode lead 6, the negative electrode lead 7, and the housing 2 of the electrode body 3 can be easily insulated. Can be.

  Further, in the normal liquid injection process, the electrolytic solution is injected from the liquid injection port formed in the lid 2b after the electrode body 3 and the like are accommodated in the case 2, and at this time, the electrode in the case 2 is injected. Since the body 3 is in a state compressed by the coil press and further receiving pressure from the housing 2, the liquid permeability to the electrode body 3 is reduced. On the other hand, when the liquid is injected into the bag-like insulating sheet 8 as in the present embodiment, the electrode body 3 in the insulating sheet 8 is not compressed and is not subjected to external pressure. It is possible to inject liquid in this state. For this reason, since the liquid permeability to the electrode body 3 is improved as compared with a normal liquid injection process, liquid injection in a short time can be realized. Moreover, it is also possible to perform coil press which suppresses the swelling of the electrode body 3 after completion | finish of liquid injection, and can also improve the insertability of the electrode body 3 to the housing | casing 2. FIG.

  In addition, before inserting the bag-shaped insulating sheet 8 into the container body 2a, the electrode body 3 in the bag-shaped insulating sheet 8 is subjected to aging (running operation) that repeats charging and discharging. Is possible. In this case, the electrode body 3, the positive electrode lead 6, the negative electrode lead 7, and the bag-like insulating sheet 8 (see FIG. 5) containing the electrolytic solution are placed in another sealed container, and aging is performed in the sealed container. I do. This sealed container is a metallic container that prevents moisture permeation. In addition to this container, it is also possible to prevent the influence of moisture on the bag-like insulating sheet 8 by placing a moisture adsorbent in the sealed container. This is because it is necessary to put the bag-like insulating sheet 8 into the housing 2 in a dry state. For example, if the bag-like insulating sheet 8 having moisture such as water droplets is accommodated in the housing 2 as it is, moisture is mixed into the housing 2 and a problem due to the influence of the moisture occurs.

  When aging is performed, gas is generated to some extent inside the bag-like insulating sheet 8 due to the aging. When degassing this gas from the insulating sheet 8, the degassing is performed by forming a discharge port for discharging the gas generated in the inside of the insulating sheet 8 by drilling or partially cutting it. After that, re-sealing is performed to seal the discharge port by thermal welding or ultrasonic welding. In this case, as shown in FIG. 5, the bag-like insulating sheet 8 has a sealing mark 14 in which a discharge port opened for degassing is sealed. By adjusting the degree of drilling or partial cutting at this time, the sealing mark 14 can be made to function as the open portion 8c. In addition, by performing aging before inserting the above-described bag-shaped insulating sheet 8 into the container body 2a, gas generated by aging can be easily removed as compared with the case of performing aging after the completion of a normal battery. .

  As described above, according to the above-described embodiment, by providing the bag-shaped insulating sheet 8 that wraps the electrode body 3 together with the electrolytic solution, the electrode body 3 and the electrolytic solution are wrapped by the bag-shaped insulating sheet 8. Is housed in the housing 2. As a result, metal powder such as welding spatter and dust is prevented from being mixed into the electrode body 3 and the electrolytic solution during production, and a complete insulation state can be formed. And the occurrence of electrolyte leakage can be reliably prevented. Furthermore, since the electrolytic solution is stored in the bag-like insulating sheet 8, the electrolytic solution is prevented from coming into direct contact with the housing 2, so that even if a crack or the like occurs in the housing 2, It is possible to reliably prevent the electrolyte from flowing out. Further, since the bag-like insulating sheet 8 is housed in the housing 2 and protected by the housing 2, it is possible to prevent the insulating sheet 8 from being damaged, and even if the damage occurs. Since the housing 2 is present, it is possible to more reliably prevent the occurrence of electrolyte leakage.

  The bag-like insulating sheet 8 is welded to the positive electrode sealing material 4b and the negative electrode sealing material 5b. Thereby, the liquid leakage of the electrolyte from between the insulating sheet 8 and the positive electrode sealing material 4b or between the insulating sheet 8 and the negative electrode sealing material 5b can be prevented. Furthermore, since the insulating sheet 8 is integrated with the lid 2b by welding the insulating sheet 8 to the positive electrode sealing material 4b and the negative electrode sealing material 5b during the manufacturing process, the handling of the insulating sheet 8 becomes easy. It is possible to facilitate the process work.

  Moreover, the bag-shaped insulating sheet 8 has an open portion 8c that is opened when the internal pressure becomes a predetermined value or more. As a result, the open portion 8c is opened when the gas is generated in the bag-like insulating sheet 8 due to the occurrence of an abnormality and the internal pressure of the bag-like insulating sheet 8 rises to a predetermined value or more. Since the gas in the insulating sheet 8 is released, the internal pressure of the insulating sheet 8 can be lowered to prevent problems such as rupture of the insulating sheet 8.

  The bag-like insulating sheet 8 has a belt-like welded portion 12 extending along the peripheral edge thereof, and the welded portion 12 is bent along the extending direction and provided in the housing 2. Yes. Since the bag-shaped insulating sheet 8 is reduced by this bending, the bag-shaped insulating sheet 8 can be easily accommodated in the housing 2. Furthermore, compared with the case where unnecessary portions are cut because the bag-like insulating sheet 8 is stored in the housing 2, it is possible to prevent foreign matters such as cut pieces and dust from being generated.

  However, if it is impossible or difficult to store in the housing 2 even after bending, the welded portion 12 is cut along the extending direction. Thereby, the welding part 12 has the cutting trace (end part shown by the lines L1-L3) extended along the extending direction. As a result, the bag-like insulating sheet 8 can be reliably and easily accommodated in the housing 2.

  Moreover, the bag-like insulating sheet 8 has a welding mark 13 in which a liquid injection port 11 for injecting an electrolytic solution is closed by welding. This welding mark 13 is a mark indicating that the liquid injection port 11 is closed by welding. Since the injection hole 11 can be reliably closed by the welding marks 13, it is possible to reliably prevent occurrence of liquid leakage of the electrolytic solution.

  The bag-like insulating sheet 8 has a sealing mark 14 in which a discharge port for discharging the gas generated inside is sealed. This sealing mark 14 is a mark indicating that the discharge port opened for degassing is sealed. Therefore, the gas generated in the bag-like insulating sheet 8 due to aging or the like can be surely extracted from the discharge port, and then the discharge port for degassing can be reliably closed by the sealing mark 14. The occurrence of electrolyte leakage can be reliably prevented.

  Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in the above-described embodiment, the insulating sheet 8 is welded to the positive electrode sealing material 4b and the negative electrode sealing material 5b. However, the present invention is not limited to this, and as shown in FIG. You may make it form 4b and the negative electrode sealing material 5b, and the insulating sheet 8 integrally. In this case, the insulating sheet 8 includes a positive electrode seal portion 21 that seals between the positive electrode terminal 4 and the lid body 2b, and a negative electrode seal portion 22 that seals between the negative electrode terminal 5 and the lid body 2b. Will have. By such integral molding, the number of parts can be reduced and the process work can be simplified.

  Moreover, in the above-mentioned embodiment, although the liquid injection port 11 is formed in the periphery of the bag-shaped insulating sheet 8, it is not restricted to this, As shown in FIG. A part of the insulating sheet 8 may be protruded and the liquid injection port 11 may be formed in that part. In this case, the bag-like insulating sheet 8 has the protruding portion 31 having the liquid injection port 11. For example, the protruding portion 31 protrudes from a corner portion of the bag-like insulating sheet 8. After the liquid injection from the liquid injection port 11 of the protruding portion 31, the tip end portion 31 a of the protruding portion 31 is welded. This tip part 31a becomes a rectangular welded part. Aging is performed in this state, and thereafter, the protruding portion 31 is directed upward and cut by a line L4 to form a discharge port, and the gas generated in the bag-like insulating sheet 8 is removed by aging. After the degassing, the base portion 31b of the protruding portion 31 is welded to close the discharge port. This base part 31b becomes a rectangular welded part. In addition, by adjusting the welding force at this time, it is possible to cause the root portion 31b to function as the opening portion 8c. By providing such a protruding portion 31, it is possible to easily perform the electrolyte injection operation, and further the degassing and sealing operations.

  In the above-described embodiment, the positive electrode sealing material 4b and the negative electrode sealing material 5b are provided as separate bodies. However, the present invention is not limited to this. For example, the positive electrode sealing material 4b and the negative electrode sealing material 5b may be integrally formed as a resin plate having them. good. In this case, the resin plate exists between the lid 2b of the housing 2 and the insulating sheet 8, and the insulating sheet 8 is welded to the back surface of the resin plate. This integral molding can reduce the number of parts and simplify the process work.

  In the step of closing the pouring port 11 in the manufacturing process according to the above-described embodiment, the pouring port 11 is welded and closed, and the opening portion that is opened when the internal pressure of the bag-like insulating sheet 8 becomes a predetermined value or more. 8c. In addition, the manufacturing process according to the above-described embodiment includes the bag-shaped insulating sheet 8 in which the liquid injection port 11 is closed before the bag-shaped insulating sheet 8 in which the liquid injection port 11 is closed is provided in the container body 2a. Before the step of bending the belt-like welded portion 12 extending along the peripheral edge of the container, or in the container main body 2a, with the bag-like insulating sheet 8 with the liquid inlet 11 closed. It has the process of cut | disconnecting the belt-shaped welding part 12 extended | stretched along the periphery of the bag-shaped insulating sheet 8 with which the opening | mouth 11 was closed along the extending | stretching direction. Before the bag-shaped insulating sheet 8 with the liquid injection port 11 closed is provided in the container body 2a, the electrode body 3 in the bag-shaped insulation sheet 8 with the liquid injection port 11 closed is charged and charged. A step of performing a leveling operation that repeats discharging, and further, after performing a leveling operation, a part of the bag-like insulating sheet 8 is opened, and a discharge port for releasing gas from the inside of the bag-like insulating sheet 8 is provided. Forming and sealing the discharge port of the bag-like insulating sheet 8 from which the gas has been released.

  DESCRIPTION OF SYMBOLS 1 ... Secondary battery, 2 ... Housing | casing, 3 ... Electrode body, 4 ... Positive electrode terminal, 4b ... Positive electrode sealing material, 5 ... Negative electrode terminal, 5b ... Negative electrode sealing material, 8 ... Insulating sheet, 8c ... Opening part, 11 ... Injection port, 12 ... welded part, 13 ... weld mark, 21 ... positive electrode seal part, 22 ... negative electrode seal part

Claims (5)

A housing,
An electrode body provided inside the housing and having a positive electrode and a negative electrode;
A positive terminal provided in the housing and electrically connected to a positive electrode of the electrode body;
A negative electrode terminal provided in the housing and electrically connected to a negative electrode of the electrode body;
The electrode body is provided inside the casing, and is capable of electrically connecting the positive electrode of the electrode body and the positive electrode terminal and the negative electrode of the electrode body and the negative electrode terminal. A bag-like insulation sheet that wraps together,
A positive electrode sealing material for sealing between the positive electrode terminal and the housing;
A negative electrode sealing material for sealing between the negative electrode terminal and the housing;
With
The secondary battery, wherein the insulating sheet is welded to the positive electrode sealing material and the negative electrode sealing material . A housing,
An electrode body provided inside the housing and having a positive electrode and a negative electrode;
A positive terminal provided in the housing and electrically connected to a positive electrode of the electrode body;
A negative electrode terminal provided in the housing and electrically connected to a negative electrode of the electrode body;
The electrode body is provided inside the casing, and is capable of electrically connecting the positive electrode of the electrode body and the positive electrode terminal and the negative electrode of the electrode body and the negative electrode terminal. A bag-like insulation sheet that wraps together,
With
The insulating sheet is
A positive seal part for sealing between the positive terminal and the housing;
A negative seal part for sealing between the negative terminal and the housing;
A secondary battery comprising: The insulating sheet has a belt-like welded portion extending along a peripheral edge thereof, and the welded portion is bent along the extending direction and provided inside the casing. The secondary battery according to claim 1 or 2 . A step of wrapping the electrode body with an insulating sheet so that the positive electrode terminal and the negative electrode terminal provided on the lid body and the positive electrode and the negative electrode of the electrode body can be electrically connected to each other with the same polarity;
Forming the insulating sheet in a bag shape while welding the peripheral edge of the insulating sheet enclosing the electrode body except a part thereof and forming a liquid injection port for injecting an electrolyte; and
Injecting an electrolytic solution from the liquid injection port into the bag-shaped insulating sheet;
Closing the liquid injection port of the bag-shaped insulating sheet into which the electrolytic solution has been injected;
Providing the bag-like insulating sheet with the liquid injection port closed in a container body having an opening at one end, closing the opening of the container body with the lid, and joining the container body and the lid;
Before wrapping the electrode body with the insulating sheet, there is a step of sealing between the positive electrode terminal and the lid body with a positive electrode sealing material and sealing between the negative electrode terminal and the lid body with a negative electrode sealing material. ,
In the step of wrapping the electrode body with the insulating sheet, the insulating sheet is welded to the positive electrode sealing material and the negative electrode sealing material . A step of wrapping the electrode body with an insulating sheet so that the positive electrode terminal and the negative electrode terminal provided on the lid body and the positive electrode and the negative electrode of the electrode body can be electrically connected to each other with the same polarity;
Forming the insulating sheet in a bag shape while welding the peripheral edge of the insulating sheet enclosing the electrode body except a part thereof and forming a liquid injection port for injecting an electrolyte; and
Injecting an electrolytic solution from the liquid injection port into the bag-shaped insulating sheet;
Closing the liquid injection port of the bag-shaped insulating sheet into which the electrolytic solution has been injected;
Providing the bag-like insulating sheet with the liquid injection port closed in a container body having an opening at one end, closing the opening of the container body with the lid, and joining the container body and the lid;
Before wrapping the electrode body with the insulating sheet, an insulating sheet having a positive electrode sealing portion and a negative electrode sealing portion is used as the insulating sheet, and the positive electrode sealing portion is interposed between the positive electrode terminal and the lid body by the positive electrode sealing portion. A method for manufacturing a secondary battery, comprising a step of sealing between a terminal and the lid by the negative electrode seal portion .

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