JP2019160452A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of up-sizing a two-dimensional code placed on a lid, while restraining reading accuracy deterioration.SOLUTION: In a secondary cell 10, a pressure release valve 30 is located closer to the terminal structure part 16 of a positive electrode than a second center axis L2, so that the midpoint of the pressure release valve 30 in the short direction of the lid 15 is located on the first center axis L1 of the lid 15. An encapsulation member 34 and a two-dimensional code 35 are placed at a position between the pressure release valve 30 and the terminal structure part 18 of the negative electrode in the longitudinal direction of the lid 15. A center axis N2 of the two-dimensional code 35 is located at a position deviated from the center axis N1 of the encapsulation member 34 in the longitudinal direction of the lid 15, and a position deviated farther to the second long edge part 15d side of the lid 15 than the first center axis L1 of the lid 15.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage device including a two-dimensional code disposed on an outer surface of a lid.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. A secondary battery generally includes an electrode assembly housed in a case and an electrolytic solution. Further, the secondary battery includes a positive electrode terminal and a negative electrode terminal fixed to the lid of the case, and the positive electrode terminal and the negative electrode terminal are electrically connected to the electrode assembly via a conductive member having the same polarity. Further, in the secondary battery, a pressure relief valve for releasing the pressure inside the case to the outside of the case is provided on the lid of the case.

  In the secondary battery manufacturing process, manufacturing information is recorded in each secondary battery, and the necessity of quick maintenance of the cause of the maintenance management and the occurrence of a failure, that is, the establishment of good traceability is being studied. In addition, the secondary battery may record information on its battery performance.

  As a method of recording manufacturing information and information on battery performance in a secondary battery, a method of providing a two-dimensional code on the outer surface of a lid is known (for example, see Patent Document 1). In the secondary battery disclosed in Patent Document 1, a plurality of two-dimensional codes are provided on the upper surface of the lid. The plurality of two-dimensional codes are arranged so as to be arranged along the longitudinal direction of the lid at the central portion in the short direction of the lid.

  A part of the plurality of two-dimensional codes is arranged between the pressure release valve arranged at the center part in the longitudinal direction and the short direction of the lid body and one terminal structure part, and the remaining two-dimensional codes are , Between the pressure relief valve and the other terminal structure.

JP 2012-113854 A

  The amount of information recorded in a two-dimensional code tends to increase in order to build good traceability and to record a lot of information about the battery performance of the secondary battery. As the amount of information recorded in the two-dimensional code increases, the size of the two-dimensional code increases.

  Further, in the secondary battery, gas is generated in the case as it is charged and discharged, and the internal pressure of the case is increased. When the pressure release valve is not open, the lid body is deformed as the internal pressure increases. As a deformation mode of the lid, there are many deformation modes in which a deformation in which the central portion in the short direction of the lid swells outwards occurs over the entire longitudinal direction of the lid. In Patent Document 1, when such a deformation mode occurs, the two-dimensional code is distorted with the deformation of the lid, and the reading accuracy of the two-dimensional code may be reduced.

  The objective of this invention is providing the electrical storage apparatus which can suppress the fall of reading accuracy while being able to enlarge the two-dimensional code which can be arrange | positioned at a cover body.

  A power storage device for solving the above problems includes a case having a rectangular box-like case main body that houses an electrode assembly, a rectangular plate-like lid closing an opening of the case main body, and the length of the lid A terminal structure portion of each pole that is disposed on both sides in the direction and transmits and receives electricity to and from the electrode assembly, and is located at a position sandwiched between the terminal structure portions in the longitudinal direction in the lid body, and the internal pressure of the case Of the pressure release valve that cleaves when the pressure reaches the open pressure and releases the internal pressure of the case to the outside of the case, and the lid among the positions sandwiched by the terminal structure portion in the longitudinal direction of the lid A sealing member having a circular shape in plan view that is close to one end of the body in the short direction and sealing a liquid injection hole for injecting an electrolyte into the case, and the terminal structure portion in the longitudinal direction in the lid Out of the sandwiched positions A power storage device that is closer to the other end in the short direction of the lid than the sealing member, and has a two-dimensional code in which solid identification information is written, and having a length in the short direction of the lid An imaginary straight line that passes through the intermediate point and extends in the longitudinal direction of the lid is defined as the first central axis of the lid, passes through an intermediate point of the longitudinal length of the lid, and is short of the lid. A virtual straight line extending in the hand direction is defined as a second central axis of the lid, and a virtual straight line that passes through an intermediate point of the sealing member along the longitudinal direction of the lid and extends in the short direction of the lid. A virtual straight line that passes through an intermediate point of the two-dimensional code along the longitudinal direction of the lid body and extends in the short direction of the lid body as a central axis line of the sealing member and a central axis line of the two-dimensional code Then, the pressure release valve is arranged closer to the one terminal structure portion than the second central axis. The sealing member and the two-dimensional code are arranged at a position sandwiched between the pressure release valve and the other terminal structure in the longitudinal direction of the lid, and the two-dimensional code is the two-dimensional code. The central axis of the cord is disposed at a position shifted in the longitudinal direction of the lid body from the central axis of the sealing member, and shifted to the other end side in the short direction of the lid body from the first central axis. The gist is that it is arranged at a position.

  According to this, the position where the central axis passes through the sealing member has the largest diameter. Therefore, if the sealing member and the two-dimensional code are arranged in the short direction of the lid, the central axis of the two-dimensional code is shifted from the central axis of the sealing member in the longitudinal direction of the lid. Accordingly, the separation distance between the sealing member and the two-dimensional code along the short direction of the lid is increased. For this reason, the dimension of the two-dimensional code which can be arrange | positioned at a cover body can be expanded in the transversal direction of a cover body. That is, the two-dimensional code that can be arranged on the lid can be enlarged. In addition, if the sealing member and the two-dimensional code are not aligned in the short direction of the lid, the dimension of the two-dimensional code that can be arranged on the lid regardless of the sealing member can be expanded in the short direction of the lid. The two-dimensional code that can be arranged on the lid can be enlarged.

  And in the electrical storage apparatus with which the enlarged two-dimensional code is arrange | positioned, gas will generate | occur | produce in a case with the charge / discharge, and the internal pressure of a case will increase. When the pressure release valve is not open, the case of the secondary battery expands and deforms as the internal pressure increases. As a deformation mode of the lid, there are many deformation modes in which a portion along the first central axis of the lid bulges outward. Even in such a deformation mode, since the two-dimensional code is arranged at a position not overlapping the first central axis of the lid, it is possible to suppress deformation of the two-dimensional code due to deformation of the lid.

  In the power storage device, the two-dimensional code is preferably arranged at a position where the central axis of the two-dimensional code is closer to the other terminal structure portion than the central axis of the sealing member.

  According to this, as an example of the manufacturing method of the pressure release valve, the lid body is pressed to form a recess in the lid body, and a valve body thinner than the plate thickness of the lid body is manufactured at the bottom of the recess to produce pressure. There is a method of using an open valve. In this method, when the lid is pressed, undulation occurs around the pressure release valve. However, since the two-dimensional code is arranged at a position farther from the pressure release valve than the sealing member, the influence of the undulation hardly reaches the two-dimensional code.

  In the power storage device, a conductive member is electrically connected to the electrode assembly, and the terminal structure portion includes a base portion electrically connected to the conductive member in the case, and a base portion to the case. A lead terminal having a shaft portion led out to the outside, and disposed on the outer surface of the lid, electrically connected to the shaft portion of the lead terminal outside the lid, and the longitudinal direction of the lid A terminal connection member extending in a longitudinal direction; an external connection terminal electrically connected to the terminal connection member; and arranged in parallel with the shaft portion in a longitudinal direction of the lid; and disposed on an outer surface of the lid. You may have the outer insulating member which insulates the said axial part, the said terminal connection member, and the said external connection terminal with the said cover body.

  According to this, the area which a terminal structure part occupies on the outer surface of a cover body is large. In a power storage device including such a terminal structure unit, a place where the two-dimensional code, the sealing member, and the pressure release valve can be arranged on the outer surface of the lid is also narrowed. However, by prescribing the arrangement of the two-dimensional code, the sealing member, and the pressure release valve, the two-dimensional code can be enlarged even if the place where the two-dimensional code can be arranged becomes narrow, and the two-dimensional code is transformed by the deformation of the lid. Deformation can be suppressed.

  The power storage device is a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to enlarge the two-dimensional code which can be arrange | positioned at a cover body, the fall of reading accuracy can be suppressed.

The perspective view which shows the secondary battery of embodiment. The top view which shows the secondary battery of embodiment. Sectional drawing which shows a terminal structure part. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 showing the pressure release valve and the sealing member. FIG. 5 is a cross-sectional perspective view taken along line 5-5 in FIG.

Hereinafter, an embodiment in which the power storage device is embodied as a secondary battery will be described with reference to FIGS.
As shown in FIG. 1, FIG. 2, or FIG. 3, the secondary battery 10 as a power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 accommodated in a case 11 and an electrolytic solution (not shown). The case 11 includes a rectangular box-shaped case main body 14 and a rectangular flat plate-shaped lid body 15 that closes the opening 14 a of the case main body 14. The lid 15 has an outer surface 15 a that faces the outside of the case 11 and an inner surface 15 b that faces the inside of the case 11. The lid 15 includes a first long edge 15c on one of a pair of long edges extending in the longitudinal direction, and a second long edge 15d on the other. The lid 15 includes a first short edge 15e on one of a pair of short edges extending in the short direction, and a second short edge 15f on the other. The secondary battery 10 of the present embodiment is a lithium ion battery.

  As shown in FIG. 3, the electrode assembly 12 includes a plurality of sheet-like positive electrodes 17 and a plurality of sheet-like negative electrodes 19. The positive electrode 17 and the negative electrode 19 are electrodes having different polarities. Although not shown in detail, the positive electrode 17 includes a positive metal foil (aluminum foil in the present embodiment) and a positive electrode active material layer present on both surfaces of the positive metal foil. The negative electrode 19 has a negative electrode metal foil (copper foil in this embodiment) and a negative electrode active material layer present on both sides of the negative electrode metal foil. The electrode assembly 12 is a laminated type in which a plurality of positive electrodes 17 and a plurality of negative electrodes 19 are interposed between separators (not shown) to insulate them.

  The positive electrode 17 has a tab 17 a having a shape protruding from a part of one side of the positive electrode 17. The negative electrode 19 has a tab 19 a having a shape protruding from a part of one side of the negative electrode 19. The plurality of positive electrode tabs 17a and the plurality of negative electrode tabs 19a are provided at positions where the positive electrode tab 17a and the negative electrode tab 19a do not overlap with each other in a state where the positive electrode 17 and the negative electrode 19 are stacked. . The electrode assembly 12 has tab-side end surfaces 12b from which the tabs 17a and 19a protrude.

  The electrode assembly 12 includes a positive electrode tab group 20 protruding from the tab-side end surface 12b. The positive electrode tab group 20 is configured by collecting and stacking all the positive electrode tabs 17 a on one end side in the stacking direction of the electrode assembly 12. The electrode assembly 12 includes a negative electrode tab group 20 protruding from the tab-side end surface 12b. The negative electrode tab group 20 is configured by collecting and laminating all the negative electrode tabs 19 a on one end side in the stacking direction of the electrode assembly 12.

  One end of the positive electrode conductive member 21 in the longitudinal direction is joined to the positive electrode tab group 20. One end side in the longitudinal direction of the negative electrode conductive member 21 is joined to the negative electrode tab group 20. Each conductive member 21 is disposed between the inner surface 15 b of the lid 15 and the tab side end surface 12 b of the electrode assembly 12.

  The secondary battery 10 includes a positive terminal structure 16 and a negative terminal structure 18. Since the positive terminal structure 16 and the negative terminal structure 18 have substantially the same configuration, common members will be described using the same member numbers.

  As shown in FIG. 1 or FIG. 3, each terminal structure portion 16, 18 includes a lead terminal 23. The lead terminal 23 is joined to the other end in the longitudinal direction of the conductive member 21. The lead terminal 23 is electrically connected to the tab group 20 via the conductive member 21. Therefore, the lead terminal 23 is electrically connected to the electrode assembly 12 through the conductive member 21. The lead terminal 23 includes a shaft portion 23 a that is electrically connected to a terminal connection member 25 described later and a base portion 23 b that is electrically connected to the conductive member 21 in the case 11 in the axial direction. The shaft portion 23 a protrudes from the base portion 23 b toward the lid body 15, passes through the lid body 15, and is drawn out of the case 11.

  Each terminal structure portion 16, 18 includes an outer insulating member 22 disposed on the outer surface 15 a of the lid 15. The outer insulating member 22 insulates the shaft portion 23 a of the lead terminal 23 from the lid body 15. The outer insulating member 22 is made of synthetic resin. The outer insulating member 22 has a rectangular shape when viewed from the outer surface 15 a of the lid 15. The length of the outer insulating member 22 extends in the longitudinal direction of the lid 15, and the short side of the outer insulating member 22 extends in the short direction of the lid 15.

  Each of the terminal structures 16 and 18 includes an external connection terminal 24 disposed outside the lid body 15. The external connection terminal 24 can fix a bus bar that electrically connects the secondary batteries 10 to the outside of the lid 15. The external connection terminal 24 is made of metal. The external connection terminal 24 is insulated from the lid 15 by the outer insulating member 22. The external connection terminal 24 and the shaft portion 23 a are arranged in parallel in the longitudinal direction of the lid body 15.

  Each terminal structure 16, 18 includes a terminal connection member 25. The terminal connection member 25 has a rectangular plate shape. The terminal connection member 25 is supported by the outer insulating member 22. The length of the terminal connection member 25 extends in the longitudinal direction of the lid body 15, and the short side of the terminal connection member 25 extends in the lateral direction of the lid body 15. An external connection terminal 24 is joined to one end side in the longitudinal direction of the terminal connection member 25. A shaft portion 23a of the lead terminal 23 is inserted into the other end side in the longitudinal direction of the terminal connection member 25 and is crimped.

  Each terminal structure 16, 18 has a seal ring 26. The shaft portion 23 a of the lead terminal 23 is inserted through the seal ring 26. The seal ring 26 is supported by the base portion 23 b of the lead terminal 23. Each of the terminal structures 16 and 18 includes an inner insulating member 27 that covers the base portion 23b of the lead terminal 23 and through which the shaft portion 23a passes. The inner insulating member 27 has a square plate shape. The inner insulating member 27 regulates the contact between the lid 15 and the extraction terminal 23 and insulates the lid 15 and the extraction terminal 23 from each other.

  The terminal structure 16 of the positive electrode is disposed on the outer surface 15 a on one end side in the longitudinal direction of the lid 15, and is disposed closer to the first short edge portion 15 e than the central portion in the longitudinal direction of the lid 15. The negative terminal structure 18 is disposed on the outer surface 15 a on the other end in the longitudinal direction of the lid 15, and is disposed closer to the second short edge portion 15 f than the central portion in the longitudinal direction of the lid 15. Of both end surfaces in the longitudinal direction of the terminal structure portion 16 of the positive electrode, an end surface closer to the central portion in the longitudinal direction of the lid 15 is defined as a positive electrode side end surface 16a. The positive electrode side end face 16 a is formed by an end face near the center in the longitudinal direction of the lid 15 among the longitudinal end faces of the outer insulating member 22. Of both end faces in the longitudinal direction of the terminal structure 18 of the negative electrode, the end face near the center in the longitudinal direction of the lid 15 is defined as a negative electrode side end face 18a. The negative electrode side end face 18 a is formed by an end face near the center in the longitudinal direction of the lid 15 among the longitudinal end faces of the outer insulating member 22.

  As shown in FIG. 2, an imaginary straight line passing through the positive electrode side end surface 16 a and extending in the short direction of the lid 15 is defined as a positive electrode side imaginary line M <b> 1, passing through the negative electrode side end surface 18 a and short of the lid 15. A virtual straight line extending in the direction is defined as a negative-side virtual line M2. When the lid 15 is viewed from the outer surface 15a side, a region sandwiched between the positive-side imaginary line M1 and the negative-side imaginary line M2 in the outer surface 15a of the lid 15 is defined as an arrangement region R. The arrangement region R is a region surrounded by the positive-side imaginary line M1, the negative-side imaginary line M2, a part of the first long edge part 15c, and a part of the second long edge part 15d in plan view. .

  The secondary battery 10 includes a pressure release valve 30 arranged in the arrangement region R of the lid body 15. When the internal pressure of the case 11 rises excessively, the case 11 expands and deforms, compressing the adjacent secondary battery 10 or device, or leaking the internal electrolyte due to breakage. Therefore, the pressure release valve 30 is cleaved when the internal pressure of the case 11 reaches an open pressure that is a predetermined pressure so that the internal pressure of the case 11 does not increase excessively, and the internal pressure of the case 11 is reduced to the case 11. Open outside. The release pressure of the pressure release valve 30 is set such that the pressure release valve 30 can be cleaved at a pressure that causes some deformation of the case 11, for example. The pressure release valve 30 has a track shape that extends in the longitudinal direction of the lid 15 in a plan view as viewed from the outer surface 15 a side of the lid 15.

  As shown in FIG. 4, the pressure release valve 30 has a plate-like valve body 31 that is thinner than the plate thickness of the lid body 15. The lid 15 has a recess 32 on the outer surface 15 a located outside the case 11. The valve body 31 is located at the bottom of the recess 32. The pressure release valve 30 is formed by pressing the lid 15 from the outer surface 15a and inner surface 15b side.

  As shown in FIG. 2, when a virtual straight line that passes through the midpoint of the length of the lid 15 and extends in the longitudinal direction of the lid 15 is defined as the first central axis L1 of the lid 15, the pressure is released. The valve 30 is located on the first central axis L1 of the lid 15. In this embodiment, the center points of the pressure release valve 30 in the longitudinal direction and the short direction are located on the first central axis L <b> 1 of the lid 15. When a virtual straight line that passes through an intermediate point of the length of the lid 15 and extends in the short direction of the lid 15 is the second central axis L2 of the lid 15, the pressure release valve 30 is The second central axis L2 does not overlap with the second central axis L2, and is disposed closer to the positive terminal structure 16 as one terminal structure than the second central axis L2. The pressure release valve 30 is arranged so that one end in the longitudinal direction thereof is located on the second central axis L2.

  The secondary battery 10 includes a liquid injection hole 33 arranged in the arrangement region R of the lid body 15. The liquid injection hole 33 has a circular hole shape in plan view as viewed from the outer surface 15a side of the lid 15. The liquid injection hole 33 penetrates the lid body 15 in the thickness direction. The liquid injection hole 33 is sealed by a sealing member 34 to prevent leakage of gas and electrolyte from the case 11. As shown in FIG. 2 or FIG. 4, the sealing member 34 includes a head 34 a having a circular shape when viewed from the outer surface 15 a side of the lid 15 and a press-fit portion 34 b press-fitted into the liquid injection hole 33. Have.

  As shown in FIG. 2, a virtual straight line that passes through the center point P <b> 2 of the sealing member 34 and extends in the short direction of the lid 15 is defined as a central axis N <b> 1 of the sealing member 34. The center axis N1 of the sealing member 34 is located closer to the terminal structure 18 of the negative electrode as the other terminal structure than the second center axis L2 of the lid 15. The sealing member 34 is not located on the second central axis L2 of the lid 15. Further, the liquid injection hole 33 and the sealing member 34 exist near one end of the lid 15 in the short direction. That is, the liquid injection hole 33 and the sealing member 34 are disposed closer to the first long edge 15c of the lid body 15 than the first central axis L1, and do not exist on the first central axis L1.

  The secondary battery 10 includes a two-dimensional code 35 arranged in the arrangement region R of the lid body 15. In the two-dimensional code 35, various types of information such as secondary battery 10 manufacturing information and battery performance are recorded. The two-dimensional code 35 is, for example, a QR code (registered trademark) and describes solid identification information of the secondary battery 10. The two-dimensional code 35 is printed on the outer surface 15a of the lid 15 by a laser. The two-dimensional code 35 has a square shape when viewed from the outer surface 15a side of the lid 15.

  A virtual straight line passing through the center point of the two-dimensional code 35 and extending in the short direction of the lid 15 is defined as a central axis N2 of the two-dimensional code 35. The central axis N2 of the two-dimensional code 35 is disposed at a position closer to the terminal structure 18 of the negative electrode as the other terminal structure than the central axis N1 of the sealing member 34. Therefore, the central axis N2 of the two-dimensional code 35 does not coincide with the central axis N1 of the sealing member 34, and is shifted to the negative electrode terminal structure 18 side along the longitudinal direction of the lid 15.

  In the sealing member 34, a location closest to the negative terminal structure 18 is defined as an inner end P, and a virtual straight line passing through the inner end P and extending in the short direction of the lid 15 is defined as a boundary line K. Further, in the two-dimensional code 35, the end portion on the first short edge portion 15e side in the longitudinal direction of the lid body 15 is defined as a first end portion 35a, and the end portion on the second short edge portion 15f side is defined as a second end portion 35b. To do.

  In a plan view of the lid body 15 as viewed from the outer surface 15a side, the two-dimensional code 35 is such that a part of the first end portion 35a side is located closer to the positive terminal structure portion 16 side than the boundary line K, and the second end portion A part on the side of 35b is located closer to the terminal structure 18 side of the negative electrode than the boundary line K. Therefore, a part of the two-dimensional code 35 on the first end 35 a side is adjacent to a part of the sealing member 34 in the short direction of the lid 15. The second end 35 b side of the two-dimensional code 35 protrudes from the boundary line K to the negative terminal structure 18 side.

  Further, the two-dimensional code 35 exists closer to the other end of the lid body 15 in the lateral direction than the sealing member 34 in the lateral direction of the lid body 15. The two-dimensional code 35 is disposed closer to the second long edge portion 15d than the first central axis L1, and does not exist on the first central axis L1. Therefore, in the arrangement region R, the two-dimensional code 35 is arranged on the opposite side of the sealing member 34 across the first central axis L1 of the lid 15, and the sealing member 34 is the first of the lid 15. It is arranged on the opposite side of the two-dimensional code 35 across the central axis L1.

Next, the effect of the secondary battery 10 will be described.
(1) The two-dimensional code 35 is arranged by shifting the central axis N2 of the two-dimensional code 35 from the central axis N1 of the sealing member 34 toward the negative terminal structure 18 side. As the central axis N2 of the two-dimensional code 35 approaches the negative terminal structure 18, the separation distance between the sealing member 34 and the two-dimensional code 35 increases, and the two-dimensional code 35 extends in the short direction of the lid 15. The dimensions can be enlarged and the two-dimensional code 35 can be enlarged. For this reason, the amount of information that can be recorded in the two-dimensional code 35 can be increased.

  (2) In the secondary battery 10 in which the enlarged two-dimensional code 35 is disposed, gas is generated in the case 11 along with the charge / discharge, and the internal pressure of the case 11 is increased. When the pressure release valve 30 is not open, the case 11 of the secondary battery 10 expands and deforms as the internal pressure increases.

  As shown in FIG. 5, as the deformation mode of the lid body 15, there are many deformation modes in which a portion along the first central axis L <b> 1 of the lid body 15 swells outward. Even in such a deformation mode, since the two-dimensional code 35 is arranged at a position shifted toward the second long edge portion 15d so as not to overlap the first central axis L1 of the lid 15, the lid It is possible to prevent the two-dimensional code 35 from being deformed by the deformation of 15. Therefore, the two-dimensional code 35 can be maintained flat, and the reading accuracy of the two-dimensional code 35 can be suppressed from decreasing.

  (3) Each terminal structure 16, 18 has an outer insulating member 22, an extraction terminal 23, an external connection terminal 24, and a terminal connection member 25, and has a shape that extends in the longitudinal direction of the lid 15. Therefore, in the lid 15, the arrangement region R of the pressure release valve 30, the sealing member 34, and the two-dimensional code 35 is a region sandwiched between the pair of terminal structure parts 16 and 18 and is a narrow region. Even in such an arrangement region R, by defining the arrangement of the pressure release valve 30, the liquid injection hole 33, and the sealing member 34, the two-dimensional code 35 is enlarged while the two-dimensional code 35 is deformed. It is possible to suppress a decrease in reading accuracy.

  (4) The central axis N2 of the two-dimensional code 35 is shifted to the negative electrode terminal structure 18 side with respect to the central axis N1 of the sealing member 34, and the two-dimensional code 35 is separated from the liquid injection hole 33 and the sealing member 34. Yes. For this reason, the thermal effect that occurs when the two-dimensional code 35 is printed by a laser is difficult to reach the liquid injection hole 33.

  (5) Since the pressure release valve 30 is formed, undulation is generated around the pressure release valve 30 when the lid 15 is pressed. However, the central axis N2 of the two-dimensional code 35 is closer to the negative terminal structure 18 than the central axis N1 of the sealing member 34, so that the two-dimensional code 35 is sealed in the longitudinal direction of the lid 15 Therefore, the two-dimensional code 35 can be hardly affected by the undulation.

In addition, you may change the said embodiment as follows.
In the embodiment, a part of the two-dimensional code 35 on the first end 35 a side is adjacent to a part of the sealing member 34 in the short direction of the lid 15. However, the central axis N1 of the sealing member 34 and the central axis of the two-dimensional code 35 are arranged so that the first end 35a side of the two-dimensional code 35 is not adjacent in the short direction of the sealing member 34 and the lid 15. N2 may be displaced in the longitudinal direction of the lid 15.

  The central axis N2 of the two-dimensional code 35 may be disposed at a position closer to the pressure release valve 30 than the central axis N1 of the sealing member 34 in the longitudinal direction of the lid body 15. That is, the positions of the sealing member 34 and the two-dimensional code 35 in the longitudinal direction of the lid 15 may be interchanged.

The two-dimensional code 35 may be rectangular when viewed from the outer surface 15a side of the lid 15.
The two-dimensional code 35 may be other than the QR code, for example, DataMtrix, MaxiCode, AztecCode, etc.

The pressure release valve 30 may be arranged at a position shifted in the short direction of the lid 15.
The pressure release valve 30 may be disposed at a position shifted toward the positive terminal structure 16 side along the longitudinal direction of the lid body 15.

The terminal structures 16 and 18 are not limited to the embodiment, and may be those in which electrode terminals are connected to the conductive member 21.
The positive electrode 17 and the negative electrode 19 may have a structure in which an active material layer exists on one side of a metal foil.

The electrode assembly may be a wound type in which a long strip-shaped positive electrode and a long strip-shaped negative electrode are wound through a long strip-shaped separator.
The power storage device can also be applied to power storage devices other than secondary batteries, such as capacitors.

  The secondary battery 10 may be a secondary battery other than the lithium ion secondary battery. In short, any ion may be used as long as ions move between the positive electrode active material and the negative electrode active material and the charge is received.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) The power storage device in which the two-dimensional code is printed on the lid by a laser.

  L1 ... first center axis, L2 ... second center axis, N1, N2 ... center axis, 10 ... secondary battery as a power storage device, 11 ... case, 12 ... electrode assembly, 14 ... case body, 14a ... opening , 15 ... Lid, 15a ... Outer surface, 16, 18 ... Terminal structure, 21 ... Conductive member, 22 ... Outer insulating member, 23 ... Lead-out terminal, 23a ... Shaft, 23b ... Base, 24 ... External connection terminal, 25 ... Terminal connection member, 30 ... Pressure release valve, 33 ... Injection hole, 34 ... Sealing member, 35 ... Two-dimensional code.

Claims (4)

A case having a rectangular box-shaped case main body for housing the electrode assembly and a rectangular plate-shaped lid for closing the opening of the case main body;
A terminal structure portion of each electrode disposed on both sides in the longitudinal direction of the lid, and for transferring electricity to and from the electrode assembly;
The lid is located at a position sandwiched by the terminal structure portion in the longitudinal direction, and is cleaved when the internal pressure of the case reaches an open pressure, thereby releasing the internal pressure of the case to the outside of the case. A pressure relief valve;
Of the position sandwiched by the terminal structure portion in the longitudinal direction in the lid, a plane that exists near one end in the short direction of the lid and seals a liquid injection hole for injecting an electrolyte into the case A circular sealing member,
Among the positions sandwiched by the terminal structure portion in the longitudinal direction in the lid, a two-dimensional code presenting solid identification information, which is closer to the other end in the short direction of the lid than the sealing member, A power storage device having
An imaginary straight line that passes through an intermediate point of the length of the lid in the short direction and extends in the longitudinal direction of the lid is a first central axis of the lid,
An imaginary straight line that passes through an intermediate point in the longitudinal direction of the lid and extends in the short direction of the lid is a second central axis of the lid,
An imaginary straight line that passes through the intermediate point of the sealing member along the longitudinal direction of the lid and extends in the short direction of the lid is a central axis of the sealing member,
When an imaginary straight line that passes through the intermediate point of the two-dimensional code along the longitudinal direction of the lid and extends in the short direction of the lid is the central axis of the two-dimensional code,
The pressure release valve is disposed closer to the one terminal structure portion than the second central axis.
The sealing member and the two-dimensional code are arranged at a position sandwiched between the pressure release valve and the other terminal structure in the longitudinal direction of the lid,
The two-dimensional code is disposed at a position where the central axis of the two-dimensional code is shifted from the central axis of the sealing member in the longitudinal direction of the lid,
The power storage device, wherein the power storage device is disposed at a position shifted from the first central axis toward the other end side in the short direction of the lid.   2. The power storage device according to claim 1, wherein the two-dimensional code is arranged at a position where a central axis of the two-dimensional code is closer to the other terminal structure portion than a central axis of the sealing member. A conductive member is electrically connected to the electrode assembly,
The terminal structure portion has a base portion electrically connected to the conductive member in the case, and a lead terminal having a shaft portion drawn from the base portion to the outside of the case,
A terminal connecting member disposed on an outer surface of the lid, electrically connected to the shaft portion of the lead terminal outside the lid, and extending in a longitudinal direction of the lid;
An external connection terminal electrically connected to the terminal connection member and arranged in parallel with the shaft in the longitudinal direction of the lid;
The power storage device according to claim 1, further comprising: an outer insulating member that is disposed on an outer surface of the lid body and insulates the shaft portion, the terminal connection member, and the external connection terminal from the lid body.   The power storage device according to any one of claims 1 to 3, wherein the power storage device is a secondary battery.