JP6094343B2 - Electricity storage element - Google Patents

Description

  The present invention relates to a structure of a power storage element.

  Conventionally, a battery such as a secondary battery has been used. The battery includes an electrode body and an electrolytic solution housed in a metal outer container. In the case of battery, in order to prevent the pressure inside the battery from rising due to heat generation due to charging / discharging and changes in environmental temperature and damaging the outer container, it breaks when the internal pressure inside the unit cell exceeds the predetermined value. Thus, a gas discharge structure for discharging the gas is provided. Conventionally, as a gas discharge structure, in addition to providing a dedicated safety valve, a technology for providing an easy-cleavage part that cleaves when the internal pressure of the outer container rises in the sealing part that seals the battery can and the lid constituting the outer container is known. (For example, Patent Document 1).

JP 2001-155698 A

  It is preferable that the easy-cleavage part provided in the joining part such as the sealing part is wide in order to improve the gas discharge capability. However, if a relatively wide easy-cleavage part is provided at the joint, at least one of the cell case such as a battery can and the lid is easily deformed when the easy-cleavage part is cleaved. In a power storage element such as a battery, an output portion including an output terminal or a conductive plate provided around the output terminal may be provided on the lid body. For this reason, when the internal pressure of the cell case is increased, the lid body is deformed and turned up, and if the lid body and the output portion come into contact with each other, there is a problem that the peripheral device is adversely affected due to a short circuit.

  In the present specification, a technique is provided that achieves both improvement of gas discharge capability and ensuring safety when the internal pressure of the cell case is increased.

  An electricity storage device disclosed in the present specification has an electrode body, an opening, and a housing space communicating with the opening, a case for housing the electrode body in the housing space, and the opening. A lid for closing, and an output unit provided on an outer surface of the lid and electrically connected to the electrode body, wherein the lid and the case are joined over the entire circumference of the opening. A joint portion is formed, and the joint portion includes at least one end portion in the first direction, and an adjacent region extending in the first direction and extending to the inner pressure of the cell case. Sometimes, an easy-cleavage part having a lower cleavage pressure than that of the other part of the joint part is provided, and in the first direction, the end of the lid on the one side and the tip of the adjacent region The distance between the lids on the one side in the first direction is Parts shorter than half the distance between the output portion.

  According to the electricity storage device disclosed in the present specification, it is possible to achieve both improvement in gas discharge capacity and ensuring safety when the internal pressure of the cell case is increased.

Single cell perspective view Single cell development Sectional drawing of the cell of Embodiment 1. Sectional view of the cell with the lid open Sectional drawing of the cell of Embodiment 2. Sectional drawing of the cell of other embodiment Sectional drawing of the cell of other embodiment

(Outline of this embodiment)
An electricity storage device disclosed in the present specification has an electrode body, an opening, and a housing space communicating with the opening, a case for housing the electrode body in the housing space, and the opening. A lid for closing, and an output unit provided on an outer surface of the lid and electrically connected to the electrode body, wherein the lid and the case are joined over the entire circumference of the opening. A joint portion is formed, and the joint portion includes at least one end portion in the first direction, and an adjacent region extending in the first direction and extending to the inner pressure of the cell case. Sometimes, an easy-cleavage part having a lower cleavage pressure than that of the other part of the joint part is provided, and in the first direction, the end of the lid on the one side and the tip of the adjacent region The distance between the lids on the one side in the first direction is Parts shorter than half the distance between the output portion.

  In this power storage element, an easy-cleavage portion is formed at a joint portion, and the formation range extends from an end portion on one side to a region adjacent to the end portion having a predetermined length. Therefore, when the easy-cleavage part is cleaved, one side of the lid body is turned up by deformation, and the gas discharge capacity can be improved as compared with the case where the easy-cleavage part is simply cleaved. In addition, since the formation range of the adjacent region is limited in the first direction as described above, even if one side of the lid is turned up, the lid is prevented from reaching the output portion, and the lid It is prevented that the body and the output unit come into contact with each other and short-circuit.

  In the above electricity storage element, a groove extending in the second direction intersecting the first direction may be provided in the vicinity of the tip of the adjacent region of the lid. According to this electricity storage device, when the easy-cleavage part is cleaved, even if the end on one side of the lid is turned up by deformation, the end on one side of the lid is bent by the groove provided in the lid. Thus, it is possible to suppress the one side of the lid body from turning over beyond the formation range of the easy-cleavage portion.

  In the above power storage element, at least the one end portion of the output portion may be covered with an insulating cover. According to this electricity storage device, one side of the lid body is turned over beyond the easy-to-break portion formation range, and even when the flipped lid body reaches the output portion, the lid body and the output portion are prevented from contacting each other. can do.

  In the above electricity storage device, the easy-cleavage part may be configured to be provided in the one end part and the other end part in the first direction, and in an adjacent region adjacent to each end part. According to this electricity storage element, since the easy-cleavage parts are provided on both sides in the first direction of the joint portion, the gas discharge capacity can be improved compared to the case where the easy-cleavage parts are provided on one side in the first direction. .

  In the power storage device, the joint portion has a rectangular shape, and includes a pair of long joint portions extending in the first direction and a pair of short joint portions extending in the second direction orthogonal to the first direction. The easy-cleavage portion may be provided in at least the entire region of the short joint portion on one side and the adjacent region adjacent to the short joint portion of the pair of long joint portions. Good. According to this electricity storage device, the easy-cleavage portion is formed in a range that extends to the adjacent region adjacent to the short joint portion of the long joint portion together with the entire short joint portion on one side. Therefore, at the time of cleavage of the easy-cleavage part, one side of the lid is easily turned by deformation.

  The electricity storage device disclosed in the present specification also includes an electrode body, an opening, and a housing space communicating with the opening, the case housing the electrode body in the housing space, and the opening. A lid that closes the portion, and an output portion that is provided on the outer surface of the lid and is electrically connected to the electrode, and the lid and the case extend over the entire circumference of the opening. Bonded to form a joint portion, and the joint portion includes at least one end portion in the first direction, and an internal region of the cell case in the adjacent region continuous with the end portion and extending in the first direction. There is provided an easy-cleavage portion having a lower cleavage pressure at the time of ascent than other portions of the joint portion, and at least one end of the output portion is covered with an insulating cover. It is good also as a structure.

  According to this electricity storage element, the easy-cleavage part is formed at the joint part, and the gas discharge capacity is increased by extending the formation range from the end part on one side to the adjacent region of the end part. Can be improved. In addition, since the formation range of the adjacent region is limited in the first direction, even if one side of the lid is turned up at the easy-cleavage portion, the lid is prevented from reaching the output portion, and the lid and A short circuit due to contact with the output unit is prevented. Furthermore, since at least one end of the output part is covered with an insulating cover, one side of the cover body is turned over beyond the formation range of the easy-cleavage part, and the turned-up cover is turned into the output part. Even when it reaches, it can prevent that a cover and an output part contact.

<Embodiment 1>
Hereinafter, Embodiment 1 will be described with reference to FIGS.
1. 1 is a secondary battery that can be repeatedly charged and discharged, and more specifically, a lithium ion battery. The plurality of unit cells 14 of the present embodiment are connected to each other by a bus bar, which is a conductive plate member, and is mounted on, for example, an electric vehicle or a hybrid vehicle, and supplies power to a power source that operates with electric energy. . The unit cell 14 is an example of a power storage element.

  As shown in FIG. 1, the unit cell 14 has a rectangular parallelepiped shape, and has a pair of short side surfaces 64 having a narrow width in the horizontal direction and a pair of long side surfaces 66 having a wide width in the horizontal direction. Hereinafter, the vertical direction in FIG. 1 is defined as the vertical direction of the unit cell 14, the direction perpendicular to the long side surface 66 is defined as the front-rear direction of the unit cell 14, and the direction perpendicular to the short side surface 64 is defined as the horizontal direction of the unit cell 14. The left-right direction is an example of the first direction, and the front-rear direction is an example of the second direction.

  As shown in FIG. 2, the single cell 14 includes a terminal unit 20, an electrode body 50, a clip 60, and a case 62. The case 62 is made of metal such as aluminum and has a rectangular parallelepiped shape, and includes the pair of short side surfaces 64, the pair of long side surfaces 66, and the bottom surface 68. The inside of the case 62 is removed to form an accommodation space 80, and the upper part is opened to form an opening 70. The opening 70 is formed longer in the left-right direction than in the front-rear direction, and communicates with the accommodation space 80 inside the case 62.

  That is, the case 62 is formed in an upper open type with the upper end open, and the flat electrode body 50 is accommodated in the accommodation space 80 of the case 62 and is filled with the electrolytic solution. The opening 70 of the case 62 is a rectangular plate member that constitutes the terminal unit 20, and is closed by the lid body 30 having substantially the same shape as the bottom surface 68.

  The terminal unit 20 includes a positive electrode terminal 22, a negative electrode terminal 24, a current collector 28, a lid body 30, and a conductive plate 32. The lid 30 is a rectangular plate member and is formed in substantially the same shape as the bottom surface 68 of the case 62. In the terminal unit 20, the lid 30 is arranged in a direction in which the short side 34 is parallel to the front-rear direction and the long side 36 is parallel to the left-right direction.

  The positive electrode terminal 22 and the negative electrode terminal 24 are arranged separately on the upper surface of the lid 30 in the left-right direction, and conductive plates 32A and 32B, which are metal plates, are arranged around the positive electrode terminal 22 and the negative electrode terminal 24. The conductive plate 32 </ b> A is disposed so as to surround the positive terminal 22 and is electrically connected to the positive terminal 22. The conductive plate 32 </ b> B is disposed so as to surround the negative electrode terminal 24 and is electrically connected to the negative electrode terminal 24. The upper surface of the lid 30 is an example of the outer surface of the lid. Moreover, what included the positive electrode terminal 22 and the electrically conductive plate 32A is an example of an output part, and what included the negative electrode terminal 24 and the electrically conductive plate 32B is another example of an output part.

  The current collectors 28A and 28B extend downward from the lower surface of the lid 30 and are electrically connected to the corresponding electrode terminals 22 and 24 via the conductive plates 32A and 32B. Each of the current collectors 28A and 28B is made of a metal plate having a sufficient thickness so as to obtain a large current capacity. The positive electrode current collector 28A is made of, for example, an aluminum alloy plate, and the negative electrode current collector 28B is For example, it consists of a copper alloy plate. The terminal unit 20 is not provided with a safety valve that breaks and releases the gas in the case 62 when the pressure in the case 62 exceeds a predetermined value.

  The electrode body 50 was wound in a flat shape in which a separator (not shown) is sandwiched between the positive electrode plate 52 and the negative electrode plate 54, the horizontal direction being the axial direction, and the width in the front-rear direction being narrower than the vertical width. It has a cylindrical shape. Each of the positive electrode plate 52 and the negative electrode plate 54 has a strip shape in the unwound state. The positive electrode plate 52 is a positive electrode current collector foil in which a positive electrode active material layer is formed on the surface of a strip-shaped aluminum foil, and an aluminum foil is exposed on the right edge without forming a positive electrode active material layer. 52A is formed. The negative electrode plate 54 has a negative electrode active material layer formed on the surface of a strip-shaped copper foil, and a negative electrode collector in which the negative electrode active material layer is not formed and the copper foil is exposed at the left edge thereof. An electric foil 54A is formed.

  In the positive electrode plate 52 and the negative electrode plate 54, the positive electrode current collector foil 52A is disposed on one end side with respect to the separator and the negative electrode plate 54, and the negative electrode current collector foil 54A is disposed on the other end side with respect to the separator and the positive electrode plate 52. It is rolled up in layers. Accordingly, only the positive electrode current collector foil 52A is laminated and protruded on one end side of the electrode body 50, and only the negative electrode current collector foil 54A is laminated and protruded on the other end side.

  The positive electrode current collector foil 52A is connected to the positive electrode current collector 28A at a side surface portion (see a two-dot chain line in FIG. 2) extending linearly in the vertical direction. In the negative electrode current collector foil 54A, a side surface portion (see a two-dot chain line in FIG. 2) extending linearly in the vertical direction is connected to the negative electrode current collector 28B.

  The current collectors 28 </ b> A and 28 </ b> B and the current collector foils 52 </ b> A and 54 </ b> A are connected by ultrasonic welding while being sandwiched between the clips 60. The clip 60 is made of a material having a resistance value equivalent to the material of the current collectors 28A and 28B and the current collector foils 52A and 54A to be welded, the positive clip 60A is made of an aluminum alloy, and the negative clip 60B is Made of copper alloy.

  In the process of manufacturing the unit cell 14, the electrode body 50 is accommodated in the case 62 in a state of being connected between the pair of current collectors 28 </ b> A and 28 </ b> B, thereby covering the opening 70 of the case 62. The lid 30 of the arranged terminal unit 20 is joined to the case 62. When the lid 30 and the case 62 are joined, the outer peripheral region on the short side 34 side of the lid 30 is laser-welded to the upper end portion of the corresponding short side 64, and the outer periphery on the long side 36 side of the lid 30. A region is laser welded to the upper end of the corresponding long side 66.

  That is, in the unit cell 14, the lid body 30 and the case 62 are joined over the entire circumference of the opening 70, thereby forming a rectangular joining portion 40 (see the dashed line in FIG. 3). The joint portion 40 is formed over the entire circumference of the opening 70, that is, the entire circumference of the lid body 30, while its cleavage strength, that is, the pressure value at which the joint portion 40 is cleaved when the pressure in the case 62 rises, Is not uniform, and an easy-cleavage portion 42 (see dotted line in FIG. 3) having a low cleavage strength is provided in a part of the joint portion 40.

2. Easy-cleavage part The easy-cleavage part 42 is provided by making the welding temperature in laser welding lower than the other parts in the joint part 40. As shown in FIG. 1, the easy-cleavage portion 42 is provided in the entire short joint portion 44 located at the upper end of the short side surface 64 in the joint portion 40. The easy-cleavage part 42 is provided in the whole area of both of a pair of short junction parts 44 extended in the front-back direction. The easy-cleavage portion 42 is also provided in the long joint portion 46 located at the upper end of the long side surface 66 in the joint portion 40. The easy-cleavage portions 42 are provided at both ends in the left-right direction of the pair of long joint portions 46 extending in the left-right direction, that is, in the adjacent regions 48A, 48B adjacent to the short joint portions 44 of the pair of long joint portions 46. ing. The short joint portion 44 is an example of an end portion on one side or the other side of the joint portion.

  The adjacent region 48A is provided at the right end of both of the pair of long joint portions 46, and the easy-cleavage portion 42 provided in the adjacent region 48A is the easy-cleavage portion 42 provided in the right short joint portion 44. Is continuous. Therefore, when the right short joint portion 44 is cleaved when the pressure in the case 62 rises, the cleaving proceeds to the left end of the adjacent region 48A. The adjacent region 48B is provided at the left end of both of the pair of long joint portions 46, and the easy-cleavage portion 42 provided in the adjacent region 48B is an easy-cleavage provided in the left short joint portion 44. It is continuous with the part 42. Therefore, when the left short joint portion 44 is cleaved when the pressure in the case 62 rises, the cleaving proceeds to the right end of the adjacent region 48B. The left end of the adjacent region 48A and the right end of the adjacent region 48B are examples of the tip of the adjacent region.

As shown in FIG. 3, the adjacent region 48 </ b> B is provided in the range of the distance L <b> 1 with the short side 34 on the left side of the lid 30 as a reference in the left-right direction. In the cell 14 of this embodiment, the distance L1 is set to be shorter than half of the distance L2 between the short side 34 on the left side of the lid 30 and the left end of the conductive plate 32B. Therefore, as shown in FIG. 4, even when the left short joint portion 44 and the adjacent region 48 </ b> B are cleaved and the left end of the lid body 30 is turned up when the pressure in the case 62 increases, the left side of the lid body 30. It is avoided that the short side 34 is in contact with the conductive plate 32B.
L1 <(L2) / 2

  Similarly, the adjacent region 48A is provided in the range of the distance L1 with respect to the short side 34 on the right side of the lid 30 in the left-right direction. In the cell 14 of this embodiment, the distance L1 is set to be shorter than half of the distance L2 between the short side 34 on the right side of the lid 30 and the right end of the conductive plate 32A. For this reason, when the pressure in the case 62 rises, even if the right short joint portion 44 and the adjacent region 48A are cleaved and the right end of the lid 30 is turned up, the right short side 34 of the lid 30 is connected to the conductive plate. Contact with 32A is avoided.

3. Advantages of the Invention (1) In the unit cell 14 of this embodiment, the easy-cleavage portion 42 is provided in the entire region of the short joint portion 44 and in the adjacent regions 48A and 48B of the long joint portion 46 adjacent to the short joint portion 44. Therefore, when one of the short joint portions 44 is cleaved when the pressure in the case 62 rises, the cleaving proceeds to the adjacent regions 48A and 48B, and as shown in FIG. 4, the short side 34 on one side of the lid 30 is It can be turned up. As a result, as shown by a two-dot chain line in FIG. 4, it is possible to realize a wide opening 72 and improve the gas discharge capacity as compared with the case where only the short joint portion 44 is cleaved.

  Therefore, it is not necessary to provide the safety valve provided in the lid 30 of the terminal unit 20 in the unit cell 14 of the present embodiment. For the formation of the safety valve, a through hole is formed in a part of the lid 30, and a safety valve that is a thin film made of a metal such as stainless steel is arranged and fixed. Process (through-hole formation, arrangement, and fixing) is required, which increases costs and reduces work efficiency. In the unit cell 14 of the present embodiment, the easy-cleavage portion 42 is provided in the entire short joint portion 44 and in the adjacent regions 48A and 48B, so that a sufficient opening 72 can be realized and no safety valve is provided. Cost reduction and work efficiency improvement can be realized.

(2) In addition, in the unit cell 14 of the present embodiment, the range in which the adjacent regions 48A and 48B in the left-right direction are formed is set so that the short side 34 on the one side and the conductive plates 32A and 32B on the one side of the lid 30 are formed. Is limited by the relationship with the distance L2. Thereby, even when the one side end of the lid 30 is turned up, it is possible to prevent the lid 30 and the conductive plates 32A and 32B from coming into contact with each other and causing a short circuit.

(3) In the unit cell 14 of the present embodiment, the easy-cleavage portions 42 are provided at both ends of the pair of short joint portions 44 and at both ends in the left-right direction adjacent to the short joint portions 44 of the long joint portion 46. Therefore, compared with the case where the easy-cleavage part 42 is provided only in the whole region of one short joining part 44 and only the edge part of the one side of the left and right direction of the long joining part 46, gas discharge capability is improved. Can do.

<Embodiment 2>
A second embodiment will be described with reference to FIG. The unit cell 14 of the present embodiment is different from the first embodiment in that the groove 74 is provided on the upper surface of the lid 30 and the insulating covers 76A and 76B are provided. In the following description, the same description as that of the first embodiment will not be repeated.

1. As shown in FIG. 5, a groove 74 is provided at a position corresponding to the right end portion of the adjacent region 48 </ b> B on the upper surface of the lid 30. The groove 74 is formed so as to cross the upper surface of the lid 30 in the front-rear direction at the position. Therefore, when the left end portion of the lid body 30 is turned up when the pressure in the case 62 rises, the lid body 30 is bent by the groove 74, and further cleavage is suppressed.

  Similarly, a groove 74 is provided at a position corresponding to the left end portion of the adjacent region 48 </ b> A on the upper surface of the lid 30. The groove 74 is formed so as to cross the upper surface of the lid 30 in the front-rear direction at the position. Therefore, even when the right end portion of the lid 30 is turned up when the pressure in the case 62 is increased, the lid 30 is bent by the groove 74, and the further progress of the cleavage is suppressed. The groove 74 may be formed on the lower surface of the lid body 30.

  The conductive plate 32B is covered with a resinous insulating cover 76B, and the conductive plate 32A is covered with a resinous insulating cover 76A. Each of the insulating covers 76A and 76B is provided with an opening 78. The upper ends of the electrode terminals 22 and 24 protrude from the opening 78 and are electrically connected to a bus bar (not shown). The insulating covers 76A and 76B are examples of covers.

2. Advantages of the Invention (1) In the unit cell 14 of the present embodiment, the groove 74 is provided on the upper surface of the lid 30, and one short joint portion 44 is cleaved, and the cleaving proceeds to the adjacent regions 48 </ b> A and 48 </ b> B. However, the lid body 30 is bent by the groove 74, and the cleavage does not proceed beyond the adjacent regions 48A and 48B.

  When the cleavage proceeds to the adjacent regions 48 </ b> A and 48 </ b> B, the pressure in the case 62 is often higher than when the cleavage stays at the short joint portion 44. In this case, the pressure of the gas released from the opening 72 at the time of cleavage is relatively strong. Strong pressure concentrates. When the pressure concentrated on the adjacent regions 48A and 48B exceeds the cleavage strength of the joint portion 40, the cleavage proceeds to the joint portion 40, and the lid 30 and the conductive plates 32A and 32B come into contact with each other and short-circuit.

  In the unit cell 14 of the present embodiment, the groove 74 is provided on the upper surface of the lid 30, and when gas is blown to the back surface of the lid 30 that has been turned up, it is bent at the portion where the groove 74 is provided. As a result, the progress of the cleavage beyond the adjacent regions 48A and 48B is suppressed, and it is possible to prevent the lid 30 and the conductive plates 32A and 32B from coming into contact with each other and causing a short circuit.

(2) Further, in the unit cell 14 of the present embodiment, the conductive plates 32A and 32B are covered with the insulating covers 76A and 76B. Therefore, even when the pressure of the gas released from the opening 72 is very high and the cleavage has proceeded to the joint portion 40, the lid 30 and the conductive plates 32A and 32B are prevented from contacting and short-circuiting. be able to.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and for example, the following various aspects are also included in the technical scope of the present invention.
(1) In the above embodiment, the unit cell 14 of the secondary battery is shown as an example of the power storage element. However, the present invention is not limited to this, and the power storage element may be a capacitor with an electrochemical phenomenon.

(2) In the above embodiment, when the easy-cleavage portion 42 is formed, the description has been given using an example in which the welding temperature in laser welding is lower than that of the other portions in the joint portion 40. The method of forming is not necessarily limited to this method.

  For example, as shown in FIG. 6, even if the short side 64 corresponding to the easy-cleavage part 42 and the upper end of the long side 66 are formed thinner than the upper end of the long side 66 corresponding to the other part. good. Thereby, even when the welding temperature in laser welding is set to be equal between the easy-cleavage portion 42 and the other portions, the tear strength of the thin portion of the upper end portions of the short side surface 64 and the long side surface 66 is weakened, The easy-cleavage part 42 can be used. In this case, the easy-cleavage portion 42 is not formed up to the short side 34 on the right side (left side) of the lid 30, but also in this case, the adjacent region 48 </ b> B is based on the short side 34 on the right side (left side) of the lid 30. As shown in FIG. 8, the right (left) end of the adjacent region 48B is not a reference.

  Similarly, as shown in FIG. 7, the outer peripheral region of the lid 30 corresponding to the easy-cleavage portion 42 may be formed thinner than the outer peripheral region of the lid 30 corresponding to other portions. Thereby, even when the welding temperature in laser welding is set equal between the easy-cleavage part 42 and other parts, the tear strength of the thin part of the outer peripheral region of the lid 30 is weakened, and the easy-cleavage part 42 It can be.

(3) In the above embodiment, when the easy-cleavage portion 42 is formed, an example of forming the entire region of both the pair of short joint portions 44 corresponding to the pair of short side surfaces 64 and the adjacent regions 48A and 48B is used. Although explained, it is not limited to this. For example, among the pair of short joint portions 44, the entire region of any one of the short joint portions 44 and only the adjacent region 48 </ b> A or the adjacent region 48 </ b> B corresponding to the one short joint portion 44 may be formed.

(4) In the second embodiment, the description has been given using the example in which the insulating covers 76A and 76B cover the entire upper surfaces and side surfaces of the conductive plates 32A and 32B. However, the present invention is not limited to this. For example, if the insulating cover 76A may be formed only in a range that covers the upper surface on the right side and the right side surface of the positive electrode terminal 22 of the conductive plate 32A, the insulating cover 76B is an upper surface on the left side of the negative electrode terminal 24 of the conductive plate 32B. And you may form only in the range which covers the left side surface.

(5) In the second embodiment, the description has been given using the example in which the groove 74 and the insulating covers 76A and 76B are provided at the same time. However, the present invention is not limited to this. For example, if it is possible to adopt a configuration in which the single cell 14 of the first embodiment is further provided with the groove 74 and the insulating covers 76A and 76B are not provided, the single cell 14 of the first embodiment is further provided with the insulating cover 76A. , 76B may be provided, and the groove 74 may not be provided.

(6) In the above-described embodiment, the case 62 has a rectangular parallelepiped shape, and the description has been made using an example in which the joint portion 40 has a rectangular shape, but the present invention is not limited thereto. For example, when the case 62 has an elliptic cylinder shape in which the vertical direction is the axial direction and the width in the front-rear direction is narrower than the width in the left-right direction, the joint portion 40 is elliptical.

  In this case, the easy-cleavage portion 42 is provided in the joining portion 40 in the long axis direction, that is, the end portion in the left-right direction, and the adjacent region 48 that is continuous with the end portion and has a predetermined width in the left-right direction. Also good. By forming the adjacent region 48 with a predetermined width in the left-right direction, it is possible to realize a state in which the end in the left-right direction of the lid 30 is turned up when the pressure in the case 62 increases. Further, similarly to the above-described embodiment, by limiting the formation range of the adjacent region 48 in the left-right direction, even when the end portion in the left-right direction of the lid 30 is turned up, the lid 30 and the conductive plates 32A, 32B. Can be prevented from contacting and short-circuiting.

(7) In the above embodiment, the lid body 30 is formed in substantially the same shape as the bottom surface 68, whereby the short side 34 of the lid body 30 is flush with the short side surface 64 of the case 62, and the length of the lid body 30 is Although the description has been made using an example in which the side 36 is on the same plane as the long side surface 66 of the case 62, the present invention is not limited thereto. For example, the lid 30 is formed wider than the bottom surface 68, the short side 34 of the lid 30 protrudes outside the case 62 from the short side 64 of the case 62, and the long side 36 of the lid 30 is the case 62. The long side 66 may protrude outside the case 62. In this case, the adjacent region 48B is formed in the range of the distance L1 with the short side 34 on the right side (left side) of the lid 30 as a reference.

(8) Although the above embodiment has been described using an example in which the terminal unit 20 is not provided with a safety valve, the present invention is not limited to this. For example, both the easy-cleavage part 42 and a safety valve may be formed. Thereby, the gas discharge capability can be further improved.

14: Cell, 22, 24: Electrode terminal, 30: Lid, 32: Conductive plate, 40: Joint part, 42: Easy-cleavage part, 44: Short joint part, 46: Long joint part, 48: Adjacent region, 62: case, 64: short side surface, 66: long side surface, 70: opening, 74: groove, 76: insulating cover

Claims (6)

An electrode body;
An opening, and a housing space communicating with the opening, and housing the electrode body in the housing space;
A lid that closes the opening;
An output unit provided on an outer surface of the lid body and electrically connected to the electrode body;
With
The lid and the case are joined over the entire circumference of the opening to form a joined portion,
In the joint part, at least one end in the first direction, and the adjacent region extending in the first direction, continuous with the end, the joint strength is low, so when the internal pressure of the cell case increases, An easy-cleavage part having a low cleavage pressure to cleave compared to other parts of the joint part is provided,
The dimension of the easy-cleavage part from the end of the lid on the one side in the first direction is between the end of the lid on the one side and the output part in the first direction. An electricity storage element that is shorter than half of the distance. The electricity storage device according to claim 1,
The electrical storage element in which the groove | channel extended in the 2nd direction which cross | intersects said 1st direction is provided in the edge part by the side of the said output part of the said easy-cleavage part of the said cover body. The electric storage element according to claim 1 or 2,
At least an end portion of the output portion in the first direction of the lid body is covered with an insulating cover. It is an electrical storage element as described in any one of Claims 1-3, Comprising:
The easy-cleavage part is an electric storage element provided including an end part in the first direction of the lid body and an end part on the opposite side of the joint part joining the lid body and the case . It is an electrical storage element as described in any one of Claims 1-4, Comprising: The said junction part is carrying out the rectangular shape, A pair of long junction part extended in said 1st direction, and said 1st direction A pair of short joints extending in a second direction perpendicular to each other,
The easy-cleavage part is a power storage element provided at least in the entire region of the short joint part on one side and in a part of the pair of long joint parts adjacent to the short joint part . An electrode body;
An opening, and a housing space communicating with the opening, and housing the electrode body in the housing space;
A lid that closes the opening;
An output portion provided on an outer surface of the lid body and electrically connected to the electrode;
With
The lid and the case are joined over the entire circumference of the opening to form a joined portion,
In the joint part, at least one end in the first direction, and the adjacent region extending in the first direction, continuous with the end, the joint strength is low, so when the internal pressure of the cell case increases, An easy-cleavage part having a low cleavage pressure to cleave compared to other parts of the joint part is provided,
The power storage element, wherein at least one end of the output unit is covered with an insulating cover.

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