JP2014107204A - Lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium ion battery which is good, for example, in workability and airtightness of a temporary sealing of a liquid injection port.SOLUTION: A lithium ion battery according to an embodiment includes a container and screws. The container is provided with a housing chamber where an electrode body and an electrolyte are stored and a liquid injection port with a screw hole shape, communicated to the housing chamber.

Description

  Embodiments described herein relate generally to a lithium ion battery.

  Conventionally, a lithium ion battery in which an electrode body and an electrolytic solution are housed in a container is known.

  In the manufacture of a lithium ion battery, as an example, after an electrolyte is poured from a liquid filling port of a container containing an electrode body, the liquid filling port is temporarily sealed with a rubber stopper. Next, the lithium ion battery is initially charged. Next, the rubber stopper is removed, and the gas generated by the initial charge is released out of the container to lower the internal pressure of the container. Next, the main sealing of the liquid injection port is performed by joining a sealing plate covering the liquid injection port to the container by, for example, laser welding.

JP 2009-48670 A

  In this type of lithium ion battery, as an example, it is desired that workability and airtightness of the temporary sealing of the liquid inlet are good.

  The lithium ion battery according to the embodiment includes a container and a screw. The container was provided with a storage chamber that accommodated the electrode body and the electrolytic solution, and a screw hole-shaped liquid injection port that communicated with the storage chamber. The screw was screwed into the liquid injection port.

FIG. 1 is a perspective view showing an example of a lithium ion battery according to the first embodiment. FIG. 2 is a cross-sectional view showing an example of a part of the lithium ion battery according to the first embodiment. FIG. 3 is a perspective view showing an example of a lithium ion battery according to the second embodiment. FIG. 4 is a cross-sectional view showing an example of a part of the lithium ion battery according to the second embodiment. FIG. 5 is a cross-sectional view showing an example of a part of the lithium ion battery according to the third embodiment. FIG. 6 is a cross-sectional view showing an example of a part of a lithium ion battery according to a modification of the third embodiment. FIG. 7 is a cross-sectional view showing an example of a part of the lithium ion battery according to the fourth embodiment. FIG. 8 is a cross-sectional view showing an example of a part of the lithium ion battery according to the fifth embodiment. FIG. 9 is a cross-sectional view showing an example of a part of the lithium ion battery according to the sixth embodiment. FIG. 10 is a bottom view showing an example of the lid of the lithium ion battery according to the sixth embodiment. FIG. 11 is a perspective view showing an example of a lithium ion battery according to the seventh embodiment. FIG. 12 is a plan view showing a container body of a lithium ion battery according to the seventh embodiment.

  Hereinafter, embodiments will be described in detail with reference to the drawings. Note that similar components are included in the following embodiments. Therefore, in the following, common reference numerals are given to those similar components, and redundant description is omitted.

(First embodiment)
As shown in FIGS. 1 and 2, the lithium ion battery 1 (secondary battery, unit cell) of this embodiment includes a container 2. A positive electrode terminal 3 and a negative electrode terminal 4 are fixed to the container 2. The container 2 contains an electrode body 5 (FIG. 2) and an electrolytic solution.

  The container 2 is a flat rectangular parallelepiped exterior container. The container 2 is comprised by the synthetic resin material as an example. The container 2 is made of, for example, an insulating synthetic resin material (for example, modified PPE (polyphenylene ether) or PFA (perfluoroalkoxyalkane, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer)). . Further, as the synthetic resin material of the container 2, a thermoplastic resin can be used. For example, PE, olefin resin such as PP and PMP, polyester resin such as PET, PBT, and PEN, POM resin, PA6, Polyamide resins such as PA66 and PA12, crystalline resins such as PPS resin and LCP resin and their alloy resins, or PS, PC, PC / ABS, ABS, AS, modified PPE, PES, PEI, PSF, etc. Amorphous resins and their alloy resins can be used.

  The container 2 includes a container body 2a having one end (upper end) opened, and a rectangular plate-shaped lid 2b that closes the opening of the container body 2a. The lid 2b and the container body 2a are coupled to each other, and the container 2 is configured to be liquid-tight and air-tight. The container body 2a and the lid 2b are joined together by welding or welding, for example. The lid 2b is an example of a wall (wall portion). Further, inside the container 2, a storage chamber 2c (chamber, FIG. 2) is provided. The storage chamber 2c stores the electrode body 5 and the electrolytic solution.

  The electrode body 5 is formed by spirally winding a positive electrode sheet and a negative electrode sheet, which are power generation elements, via a separator, or by laminating a positive electrode sheet and a negative electrode sheet via a separator.

  As shown in FIG. 1, the positive terminal 3 (first terminal) is provided at one end of the lid 2b in the longitudinal direction. On the other hand, the negative electrode terminal 4 (second terminal) is provided at the other end in the longitudinal direction of the lid 2b. The positive electrode terminal 3 and the negative electrode terminal 4 are provided through the lid 2 b and connected to the positive electrode and the negative electrode of the electrode body 5, respectively. The positive electrode terminal 3 and the negative electrode terminal 4 protrude outward from the outer surface 2f (upper surface) of the lid 2b.

  The lid 2b is provided with a safety valve 2d (valve). The safety valve 2d is positioned between the positive terminal 3 and the negative terminal 4 as an example. The safety valve 2d is formed in a rectangular shape as an example. The safety valve 2d opens the container 2 when the pressure in the container 2 increases. As an example, the safety valve 2d is formed by thinning a part of the lid 2b to about half the thickness. A stamp is formed on the upper surface of the safety valve 2d. When gas is generated in the container 2 and the internal pressure of the container 2 rises to a predetermined value or more, the safety valve 2d breaks and opens, releases the gas in the container 2 and lowers the internal pressure of the container 2.

  Further, as shown in FIG. 2, the lid 2b is provided with a liquid injection port 2e (opening, opening). The liquid injection port 2e is a through-hole penetrating the lid 2b in the thickness direction of the lid 2b and communicates with the storage chamber 2c. The liquid injection port 2e is formed in a screw hole shape as an example. That is, a female thread portion is provided on the peripheral surface (hole peripheral surface) of the liquid injection port 2e. The electrolytic solution is injected into the container 2 (accommodating chamber 2c) from the liquid injection port 2e.

  A screw 6 is screwed into the liquid injection port 2e. As an example, the screw 6 has a head portion 6a and a shaft portion 6b. As an example, the screw 6 is a bolt. The head 6a is overlaid on the outer surface 2f of the lid 2b. An outer surface 2 f of the lid 2 b constitutes a part of the outer surface of the container 2. The shaft portion 6b extends from the head portion 6a. The shaft portion 6b is provided with a male screw portion screwed with the female screw portion of the liquid injection port 2e. In the present embodiment, as an example, the screw 6 is made of a synthetic resin material. As an example, the screw 6 is made of the same material as the container 2.

  As shown in FIGS. 1 and 2, the lid 2b is provided with a surrounding portion 2g. The surrounding portion 2g protrudes from the outer surface 2f of the lid 2b at a position around the liquid injection port 2e. The surrounding portion 2g is provided in an annular shape (for example, an annular shape). The surrounding portion 2g surrounds the side surface 6c (surface, peripheral surface, FIG. 2) of the head 6a of the screw 6. In the present embodiment, as an example, the surrounding portion 2g is integrally formed with the lid 2b and constitutes a part of the lid 2b. Moreover, the top part 2h (front-end | tip part) of the surrounding part 2g protrudes rather than the head 6a from the outer surface 2f as an example, and the whole head 6a is accommodated in the inside of the surrounding part 2g.

  Next, an example of a method for manufacturing the lithium ion battery 1 will be described. First, an electrolytic solution is injected into the container 2 from the liquid injection port 2e using an electrolytic solution injection device (not shown) (liquid injection process). Next, the ambient atmosphere of the container 2 into which the electrolytic solution has been injected is brought into a reduced pressure state (a reduced pressure step). Next, the liquid injection port 2e is temporarily sealed by screwing the screw 6 into the liquid injection port 2e under a reduced pressure environment (temporary sealing step). Next, the lithium ion battery 1 is initially charged (charging process). Next, after a predetermined period from the completion of initial charging, the screw 6 is removed from the liquid injection port 2e, and the liquid injection port 2e is opened (gas venting step). Thereby, the gas in the container 2 generated by the initial charging is released from the liquid injection port 2e, and the pressure in the container 2 becomes a predetermined pressure or less. Thus, the performance of the lithium ion battery 1 can be improved by releasing the gas generated by the initial charging to the outside of the container 2. Next, the screw 6 is screwed into the liquid injection port 2e again to fully seal the liquid injection port 2e (main sealing step). Finally, a predetermined inspection such as a shipping test is performed (inspection process). Thus, in this embodiment, since the liquid inlet 2e is sealed with the screw 6, the liquid inlet 2e can be easily and repeatedly sealed.

  As described above, in the lithium ion battery 1 of the present embodiment, the liquid injection port 2e has a screw hole shape, and the screw 6 is screwed into the liquid injection port 2e. Therefore, as an example, when the liquid injection port is temporarily sealed under a reduced pressure environment, it is only necessary to screw the screw 6 into the liquid injection port 2e, so that there is an advantage that workability is good. Moreover, since it is a coupling | bonding of the screw 6 and a screw hole (injection port 2e), there exists an advantage that airtightness is favorable. On the other hand, when the liquid injection port is temporarily sealed with a rubber plug, it is difficult to position the rubber plug when the rubber plug is pushed into the liquid injection port, or the rubber plug is displaced from the liquid injection port, resulting in low airtightness. There is a case.

  Moreover, in the lithium ion battery 1 of this embodiment, since the injection hole 2e is screw hole shape and the screw 6 is screwed in the said injection hole 2e, the sealing (main sealing) of an injection hole is favorable. There is an advantage of being. On the other hand, if the container provided with the liquid injection port is made of metal and the liquid injection port is sealed by joining a metal sealing plate covering the liquid injection port to the container, for example, by laser welding. Electrolytic solution may adhere to the periphery of the liquid port, resulting in poor welding, and the liquid injection port may not be sealed well.

  Moreover, according to the lithium ion battery 1 of this embodiment, since the container 2 (lid 2b) provided with the injection port 2e and the screw 6 are the same synthetic resin material, compared with the case where those materials differ. The liquid injection port 2e is sealed well.

  Moreover, according to the lithium ion battery 1 of this embodiment, since the screw | thread 6 is comprised with resin, it can suppress that a short circuit generate | occur | produces.

(Second Embodiment)
As shown in FIGS. 3 and 4, the present embodiment is different from the first embodiment in that a covering member 7 is provided on the container 2 in the lithium ion battery 1 </ b> A.

  The covering member 7 covers the opposite side of the shaft 6b of the head 6a and is coupled to the surrounding part 2g. As an example, the cover member 7 includes a circular plate portion 7a and an annular annular portion 7b provided on the periphery of the plate portion 7a. In the cover member 7, the annular portion 7b is coupled to the top portion 2h of the surrounding portion 2g. In the present embodiment, as an example, the covering member 7 is separated from the head 6a. The covering member 7 is made of a synthetic resin material. As an example, in this embodiment, the covering member 7, the container 2, and the screw 6 are made of the same synthetic resin material. As an example, the covering member 7 is welded to the surrounding portion 2g by hot plate welding or the like. As an example, the entire region of the tip of the annular portion 7b is welded to the top 2g of the surrounding portion 2g. Since the cover member 7 and the surrounding portion 2g are thermally welded, the airtightness between them is ensured. In the present embodiment, the surrounding portion 2g corresponds to a coupling portion where the covering member 7 in the container 2 is coupled.

  The covering member 7 constitutes the accommodating portion 8 together with the surrounding portion 2g. That is, the accommodating portion 8 includes the covering member 7 and the surrounding portion 2g. The accommodating portion 8 is provided so as to protrude from the outer surface 2f of the lid 2b. The accommodating portion 8 accommodates the head 6 a of the screw 6. In addition, the accommodating portion 8 further seals the liquid injection port 2 e from the outside of the screw 6.

  Next, an example of a manufacturing method of the lithium ion battery 1A will be described. In this embodiment, a liquid injection process, a pressure reduction process, a temporary sealing process, a charging process, and a degassing process are the same as those in the first embodiment, and the main sealing process is different from that in the first embodiment. In the main sealing step of the present embodiment, the screw 6 is screwed into the liquid injection port 2e, whereby the liquid injection port 2e is main-sealed, and then the covering member 7 is welded to the surrounding portion 2g, for example, by hot plate welding. Thereafter, an inspection process is performed.

  As described above, according to the lithium ion battery 1 </ b> A of the present embodiment, since the accommodating portion 8 is provided, the liquid injection port 2 e is double sealed by the screw 6 and the accommodating portion 8. The main sealing of the liquid injection port 2e is ensured better. Further, as an example, since the cover member 7 of the housing portion 8 is welded to the surrounding portion 2g, the airtightness between the covering member 7 and the surrounding portion 2g is high. As an example, the screw 6 can be protected by the accommodating portion 8.

  The cover member 7 may be provided with a safety valve similar to the safety valve 2d. In this case, when the internal pressure of the container 2 exceeds a specified level due to the gas generated in the container 2, as an example, at least one of the screw 6 and the liquid injection port 2e is deformed, and the screw 6 and the liquid injection port The gas may be discharged into the accommodating portion 8 through the gap formed between the two and the safety valve, and the safety valve may be activated when the pressure in the accommodating portion 8 exceeds a specified level.

(Third embodiment)
As shown in FIG. 5, in the present embodiment, in the lithium ion battery 1B, the washer 9 as a sealing member (elastic member) is provided between the container 2 and the head 6a of the screw 6 as described above. Different from the embodiment. FIG. 5 shows an example in which the present embodiment is applied to the second embodiment.

  As an example, the washer 9 is made of an elastic member such as rubber and has elasticity. As a material for the washer 9, fluororubber having high chemical resistance is suitable. The washer 9 is formed in an annular shape (for example, an annular shape). A shaft portion 6b of the screw 6 is inserted into the washer 9, and the washer 9 is sandwiched between the container 2 (the outer surface 2f of the lid 2b) and the head portion 6a of the screw 6.

  As described above, in this embodiment, since the annular washer 9 is provided between the container 2 and the head 6a of the screw 6, the unevenness of the outer surface 2f of the lid 2b that is the seating surface of the screw 6 is provided. The airtightness between the screw 6 and the outer surface 2f is improved. The screw 6 and the container 2 may be made of a metal material instead of a synthetic resin material.

  Next, a modification of this embodiment will be described. As shown in FIG. 6, the lithium ion battery 1 </ b> C of the present modification is provided with an O-ring 9 </ b> A instead of the washer 9 between the container 2 and the head 6 a of the screw 6. The O-ring 9A is an example of a seal member. The O-ring 9A, for example, is configured by an elastic member such as rubber and has elasticity. As a material for the O-ring 9A, fluororubber having high chemical resistance is suitable. The O-ring 9A is formed in an annular shape (for example, an annular shape). The shaft 6b of the screw 6 is inserted into the O-ring 9A, and the O-ring 9A is sandwiched between the container 2 (the outer surface 2f of the lid 2b) and the head 6a of the screw 6. As an example, the O-ring 9A is fitted in an annular recess 2i provided on the outer surface 2f of the lid 2b. Even with such a configuration, like the washer 9, the airtightness between the screw 6 and the outer surface 2f is improved.

(Fourth embodiment)
As shown in FIG. 7, the present embodiment is different from the above-described embodiment in that the covering member 7 is bonded (for example, welded) to the head 6 a of the screw 6 in the lithium ion battery 1 </ b> D. FIG. 4 shows an example in which the present embodiment is applied to the third embodiment. The covering member 7, the container 2, and the screw 6 are made of the same material (for example, a synthetic resin material), and the covering member 7 is welded to the head portion 6a and the surrounding portion 2g by hot plate welding or the like. ing. As another example, the covering member 7 may be bonded to the head portion 6a and the surrounding portion 2g by adhesion or the like. In this case, the cover member 7, the screw 6, and the container 2 may be made of a metal material instead of the synthetic resin material.

  As described above, in the present embodiment, the covering member 7 is coupled to the head 6 a of the screw 6. Therefore, the cover member 7 can suppress the screw 6 from being loosened.

  In order to prevent loosening (rotation prevention) of the head 6 a of the screw 6, an uneven fitting structure may be provided at the boundary portion between the covering member 7 and the container 2.

(Fifth embodiment)
As shown in FIG. 8, the present embodiment is different from the above-described embodiment in that the container 2 has a metal part 2j and a resin part 2k in a lithium ion battery 1E. FIG. 8 shows an example in which the present embodiment is applied to the fourth embodiment.

  The metal part 2j (metal can) is made of a metal material and includes a container body 2a and a part 2b1 of the lid 2b. A part 2b1 of the lid 2b has a plate shape including the peripheral edge of the lid 2b. The metal part 2j is provided with a storage chamber 2c. The metal part 2j is made of a metal material such as aluminum or an aluminum alloy, for example.

  The resin portion 2k is made of a synthetic resin material and constitutes a part of the lid 2b. The resin part 2k has a substantially cylindrical shape. The resin portion 2k is provided with a liquid injection port 2e. Moreover, the resin part 2k has the surrounding part 2g. The resin part 2k is comprised with the same synthetic resin material as the lid | cover 2b of 1st Embodiment as an example. Then, a screw 6 made of a synthetic resin material is screwed into a liquid injection port 2e provided in the resin portion 2k. Further, the cover member 7 is joined (welded) to the resin portion 2k to constitute the accommodating portion 8. As an example, the resin part 2k is integrated (coupled) with the metal part 2j by insert molding.

  As an example, a concavo-convex structure 2m (a concave portion, a convex portion, a concave groove, a protrusion, or the like) is provided at a boundary portion between the metal portion 2j and the resin portion 2k. The uneven structure 2m is formed in an annular shape (annular shape) around an axis along the thickness direction of the lid 2b. Therefore, according to the present embodiment, as an example, the path at the boundary portion becomes long, and the pressure loss (flow resistance) at the boundary portion increases, so that airtightness is likely to increase. Further, the boundary portion can be subjected to a surface treatment for increasing the bonding force (bonding force) between the metal material and the synthetic resin material. This surface treatment is, for example, an edging treatment for forming fine holes in the joint surface between the metal portion 2j and the resin portion 2k.

  As described above, in the lithium ion battery 1E of the present embodiment, the liquid injection port 2e has a screw hole shape, and the screw 6 is screwed into the liquid injection port 2e. Therefore, similarly to the first embodiment, as an example, when the liquid injection port is temporarily sealed, there is an advantage that workability is good because the screw 6 only needs to be screwed into the liquid injection port 2e. Moreover, since it is a coupling | bonding of the screw 6 and a screw hole (injection port 2e), there exists an advantage that airtightness is favorable.

  Moreover, according to the lithium ion battery 1E of this embodiment, since the accommodating part 8 is provided, the main sealing of the liquid injection port 2e by the screw 6 and the accommodating part 8 as an example similarly to 1st Embodiment. Is better secured. Further, as an example, since the cover member 7 of the housing portion 8 is welded to the surrounding portion 2g, the airtightness between the covering member 7 and the surrounding portion 2g is high. As an example, the screw 6 can be protected by the accommodating portion 8.

(Sixth embodiment)
As shown in FIGS. 9 and 10, in the present embodiment, in the lithium ion battery 1F, the rib 2p is provided on the inner surface 2n of the lid 2b. The rib 2p surrounds the liquid injection port 2e. The rib 2p surrounds the shaft portion 6b of the screw 6 protruding into the accommodation chamber 2c. The protruding amount (height) of the rib 2p from the inner surface 2n is larger than the protruding amount of the shaft portion 6b protruding into the storage chamber 2c. The rib 2p is closer to the electrode body 5 than the shaft portion 6b.

  As described above, according to this embodiment, since the rib 2p is provided on the inner surface 2n of the lid 2b, there is an advantage that the rigidity of the lid 2b is high. Moreover, since the rib 2p is closer to the electrode body 5 than the shaft part 6b, it can suppress that the shaft part 6b and the electrode body 5 contact | win.

(Seventh embodiment)
As shown in FIGS. 11 and 12, the lithium ion battery 1G (secondary battery, battery module, battery unit) of the present embodiment is a single battery unit corresponding to any of the lithium ion batteries 1 to 1F of the above-described embodiment. A plurality of 100 are provided. The single cell units 100 are stacked on each other and connected to each other. In addition, in FIG. 11, the example of the cell part 100 equivalent to the lithium ion battery 1 is shown.

  The lithium ion battery 1G has a container 2G. The container 2G has a container main body 2aG having one end (upper end) opened and provided with a plurality of storage chambers 2c, and a rectangular plate-shaped lid 2bG closing the opening of the container main body 2aG. The lid 2bG and the container body 2aG are coupled to each other, and the container 2G is configured to be liquid-tight and air-tight. The container body 2a and the lid 2b are joined together by welding or welding, for example. Each accommodating chamber 2c accommodates the electrode body 5 and the electrolytic solution. That is, in the present embodiment, a plurality of storage chambers 2c that store the electrode body 5 and the electrolytic solution are provided.

  As an example, the screw 6 (the liquid injection port 2e (not shown in FIG. 11)) and the safety valve 2d are arranged in a staggered manner. With such an arrangement, the distance between the safety valves 2d becomes longer than when the safety valves 2d are arranged in a line, so that the strength of the container 2G can be improved.

  According to the present embodiment having the above configuration, the same effects as those of the above-described embodiment can be obtained.

  According to each embodiment described above, it is possible to obtain lithium ion batteries 1 to 1G having good workability and airtightness of the temporary sealing of the liquid injection port 2e.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of 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.

  DESCRIPTION OF SYMBOLS 1-1G ... Lithium ion battery, 2 ... Container, 2c ... Storage chamber, 2e ... Injection hole, 2g ... Enclosure, 2j ... Metal part, 2k ... Resin part, 5 ... Electrode body, 6 ... Screw, 6a ... Head Part 6b ... shaft part 7 ... covering member 8 ... accommodating part 9 ... washer (sealing member), 9A ... O-ring (sealing member).

Claims (11)

A container provided with a storage chamber containing an electrode body and an electrolyte, and a screw hole-shaped liquid injection port communicating with the storage chamber;
A screw screwed into the liquid injection port;
Lithium ion battery with   The lithium ion battery according to claim 1, wherein the container and the screw are made of a synthetic resin material. The container includes a metal part made of a metal material and provided with the storage chamber, and a resin part made of a synthetic resin material and provided with the liquid injection port and coupled to the metal part,
The lithium ion battery according to claim 1, wherein the screw is made of a synthetic resin material. The screw has a head portion overlaid on the outer surface of the container, and a shaft portion extending from the head portion and screwed into the liquid injection port.
The lithium ion according to any one of claims 1 to 3, wherein a seal member is provided between the container and the head and the shaft portion is inserted and sandwiched between the container and the head. battery.   The lithium ion battery according to claim 4, wherein the seal member is a washer.   The lithium ion battery according to claim 4, wherein the seal member is an O-ring. The screw has a head portion overlaid on the outer surface of the container, and a shaft portion extending from the head portion and screwed into the liquid injection port.
4. The lithium according to claim 1, wherein the container is provided with a housing portion that has a covering member that covers the side of the head opposite to the shaft portion and that houses the head. Ion battery.   The lithium according to any one of claims 4 to 6, wherein the container is provided with a housing portion that has a covering member that covers the side of the head opposite to the shaft portion and that houses the head. Ion battery. The accommodating portion has a surrounding portion surrounding a side surface of the head portion,
The lithium ion battery according to claim 7 or 8, wherein the covering member is coupled to the surrounding portion.   The lithium ion battery according to claim 7, wherein the covering member is coupled to the head.   11. The lithium ion battery according to claim 7, wherein the coupling portion of the container to which the covering member is coupled, the covering member, and the screw are made of the same material.

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