JP2019040664A - Secondary battery - Google Patents

Abstract

To provide a secondary battery capable of suppressing variation in the working pressure of a valve body for ejecting gas in the enclosure.SOLUTION: A secondary battery includes an enclosure internally receiving a battery element, and having a through hole 40, a valve body 71 having an outside opposite part 73 facing the outside surface 121a of the enclosure and an inside opposite part 74 facing the inside surface 121b of the enclosure, and inserted into the through hole 40, an elastic energization member 75 placed between the inside opposite part 74 and the inside surface 121b of the enclosure, and energizing the inside opposite part 74 in the direction receding from the inside surface 121b of the enclosure, and a seal member 76 placed between the outside opposite part 73 and the outside surface 121a of the enclosure, and sealing the interior of the enclosure when being clamped by the outside opposite part 73 and the outside surface 121a of the enclosure with the energization force of the elastic energization member 75, where a ventilation passage 75a communicating with the through hole 40 is formed in the elastic energization member 75.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a secondary battery.

  As a document disclosing a conventional secondary battery, for example, Japanese Patent Application Laid-Open No. 2017-022050 (Patent Document 1) is cited.

  In the secondary battery disclosed in Patent Document 1, a valve body that closes the communication path is arranged in the middle of the communication path that communicates the outside and the inside of the housing. An elastic member that urges the valve body toward the inside of the housing is disposed at a portion located on the outside of the body. When the internal pressure of the housing rises above a predetermined pressure, the valve body moves toward the outside of the housing against the biasing force of the elastic member, thereby Communicate.

Japanese Unexamined Patent Publication No. 2017-022050

  However, in the secondary battery disclosed in Patent Document 1, since the elastic member is disposed outside the valve body, the elastic member is always exposed to the outside air. For this reason, there is a concern that the elastic member is deteriorated by moisture or the like contained in the outside air. In this case, there is a concern that the elastic coefficient of the elastic member changes and the operating pressure of the valve body fluctuates.

  The present disclosure has been made in view of the above problems, and an object of the present disclosure is to suppress variation in the operating pressure of the valve body for releasing the gas in the housing to the outside. The next battery is to provide.

  A secondary battery according to the present disclosure includes a casing that houses a battery element therein and has a through hole, an outer facing portion that faces the outer surface of the casing, and an inner facing portion that faces the inner surface of the casing. And is disposed between the valve body inserted into the through hole, the inner facing portion and the inner surface of the casing, and the inner facing portion is moved away from the inner surface of the casing. An elastic urging member for urging, the outer urging member and the outer surface of the housing are arranged between the outer urging member and the outer surface of the housing, and are urged by the urging force of the elastic urging member. And a sealing member that seals the inside of the housing, and the elastic biasing member is formed with a ventilation path communicating with the through hole.

  In such a configuration, in a state where the inside of the casing is sealed from the outside of the casing, the elastic biasing member is disposed inside the sealed casing. For this reason, it can suppress that an elastic biasing member deteriorates with the water | moisture content contained in external air. Thereby, the fluctuation | variation of the elastic coefficient of an elastic biasing member can be suppressed, and as a result, it can suppress that the working pressure of a valve body varies.

  According to the present disclosure, it is possible to provide a secondary battery that can suppress variation in the operating pressure of the valve body for releasing the gas in the housing to the outside.

It is a perspective view which shows the external appearance of the secondary battery which concerns on embodiment. It is sectional drawing of the secondary battery which concerns on embodiment. It is sectional drawing which shows the gas release valve which concerns on embodiment. It is sectional drawing along the IV-IV line shown in FIG. It is sectional drawing which shows the state of the gas release valve when the internal pressure of the housing | casing of the secondary battery which concerns on embodiment rises.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

  FIG. 1 is a perspective view showing the appearance of the secondary battery according to the embodiment. FIG. 2 is a cross-sectional view of the secondary battery according to the embodiment. With reference to FIG. 1 and FIG. 2, the secondary battery which concerns on embodiment is demonstrated.

  As shown in FIGS. 1 and 2, secondary battery 1 according to the embodiment is, for example, a lithium ion secondary battery. A plurality of secondary batteries 1 are connected in series to form an assembled battery (not shown) having a desired voltage. This assembled battery can be mounted on, for example, an electric vehicle (not shown) such as a hybrid vehicle.

  The secondary battery 1 includes a housing 10 and an electrode body 20. The housing | casing 10 is formed in the flat rectangular parallelepiped shape. The housing 10 accommodates an electrode body 20 as a battery element therein.

  The housing 10 includes a case body 11 having a substantially rectangular parallelepiped shape in which an opening 10 a that opens in one direction is formed, and a lid 12 that closes the opening provided in the case body 11. The case body 11 and the lid body 12 are made of a metal material such as aluminum and are welded to each other.

  The electrode body 20 includes a positive electrode sheet, a negative electrode sheet, and a separator (all not shown). The positive electrode sheet and the negative electrode sheet are wound through a separator. In addition, the positive electrode sheet and the negative electrode sheet may be laminated via a separator. A positive electrode exposed portion 25 and a negative electrode exposed portion 26 are respectively provided at one end and the other end of the electrode body 20.

  The lid body 12 is provided with a safety valve 30, a through hole 40, and a gas release valve 70. The safety valve 30 is activated when the internal pressure of the housing 10 increases and reaches a predetermined pressure P1, thereby preventing the housing 10 from bursting. The through hole 40 is provided so as to penetrate the lid body 12. The gas release valve 70 is provided in the through hole 40. In a state before the gas release valve 70 is installed, the through hole 40 functions as an injection hole used for injecting the electrolyte into the housing 10. The details of the gas release valve 70 will be described later with reference to FIGS.

  The secondary battery 1 further includes a positive electrode terminal 50 and a negative electrode terminal 60. The positive electrode terminal 50 and the negative electrode terminal 60 are provided on the lid body 12. The positive electrode terminal 50 and the negative electrode terminal 60 are provided at intervals in the long side direction of the housing 10 (left and right direction in FIG. 2).

  The positive terminal 50 includes a bolt 51, a positive external terminal 52, a rivet member 53, an insulator 54, and a gasket 55. The bolt 51, the positive electrode external terminal 52, and the rivet member 53 are formed of a conductive material (for example, a metal material such as aluminum or copper).

  The bolt 51 is provided so as to protrude upward from the lid body 12. Bolt 51 is configured to be fastened to a bolt (not shown) on the negative electrode side of another secondary battery adjacent to secondary battery 1 using a nut and a bus bar. The rivet member 53 is provided at a distance from the bolt 51, and the rivet member 53 is inserted into an insertion hole 12 a formed in the lid body 12.

  The positive electrode external terminal 52 has a thin plate shape extending between the bolt 51 and the rivet member 53, and electrically connects the bolt 51 and the rivet member 53. The rivet member 53 is electrically connected to the current collecting electrode 56 inside the housing 10.

  The insulator 54 and the gasket 55 are made of an insulating material. Examples of the insulating material include a resin material such as PFA (perfluoroalkoxy fluororesin) or a rubber material such as EPDM (ethylene propylene diene rubber).

  The insulator 54 is disposed between the positive external terminal 52 and the lid 12 and electrically insulates the positive external terminal 52 and the lid 12. The gasket 55 is disposed between the lid body 12 and the upper end portion of the current collecting electrode 56, and electrically insulates the lid body 12 and the current collecting electrode 56 and seals the housing 10.

  The secondary battery 1 further includes a current collecting electrode 56. The collecting electrode 56 is housed inside the housing 10. The current collecting electrode 56 electrically connects the rivet member 53 and the positive electrode exposed portion 25. The current collecting electrode 56 is made of a conductive material.

  The negative electrode terminal 60 includes a bolt 61, a negative electrode external terminal 62, a rivet member 63, an insulator 64, and a gasket 65.

  The bolt 61 is provided so as to protrude upward from the lid body 12. The bolt 61 is configured to be fastened to a bolt (not shown) on the positive electrode side of another secondary battery adjacent to the secondary battery 1 using a nut and a bus bar. The rivet member 63 is provided at a distance from the bolt 61, and the rivet member 63 is inserted into an insertion hole 12 b formed in the lid body 12.

  The negative electrode external terminal 62 has a thin plate shape extending between the bolt 61 and the rivet member 63, and electrically connects the bolt 61 and the rivet member 63. The rivet member 63 is electrically connected to the current collecting electrode 66 inside the housing 10.

  The insulator 64 is disposed between the negative electrode external terminal 62 and the lid body 12 and electrically insulates the negative electrode external terminal 62 and the lid body 12. The gasket 65 is disposed between the lid body 12 and the upper end portion of the current collecting electrode 66, and electrically insulates the lid body 12 and the current collecting electrode 66 and seals the housing 10. The insulator 64 is made of substantially the same material as the insulator 54.

  The secondary battery 1 further includes a current collecting electrode 66. The collecting electrode 66 is housed inside the housing 10. The current collecting electrode 66 electrically connects the rivet member 63 and the negative electrode exposed portion 26. The current collecting electrode 66 is made of a conductive material.

  FIG. 3 is a cross-sectional view showing the gas release valve according to the embodiment. 4 is a cross-sectional view taken along line IV-IV shown in FIG. With reference to FIG. 3 and FIG. 4, the gas release valve 70 which concerns on embodiment is demonstrated.

  As shown in FIGS. 3 and 4, the gas release valve 70 includes a valve body 71, an elastic biasing member 75, and a seal member 76.

  The valve body 71 is inserted into the through hole 40 provided in the thin portion 121 of the lid body 12. The valve body is inserted into the through hole 40 so that one end side is located outside the housing 10 and the other end side is located inside the housing 10. As a material of the valve body 71, for example, a rubber material and a resin material can be employed.

  The valve body 71 includes a main body 72, an outer facing portion 73, and an inner facing portion 74. The main body 72 has a substantially cylindrical shape. The outer facing portion 73 and the inner facing portion 74 are provided so as to face each other along the axial direction of the main body portion 72.

  The outer facing portion 73 is provided so as to protrude outward in the radial direction of the main body 72 from the peripheral surface on one end side of the main body 72 positioned outside the housing 10. The outer facing portion 73 faces the outer surface 121a of the casing 10 (specifically, the outer surface of the lid body 12) outside the casing 10. Specifically, the outer facing portion 73 faces the outer surface 121a of the housing 10 located around the through hole 40. The outer facing portion 73 covers the through hole 40 when viewed along the axial direction of the main body portion 72.

  The inner facing portion 74 is provided so as to protrude outward in the radial direction of the main body portion 72 from the peripheral surface on the other end side of the main body portion 72 located inside the housing 10. The inner facing portion 74 faces the inner surface 121b of the casing 10 (specifically, the inner surface of the lid body 12) inside the casing 10. Specifically, the inner facing portion 74 faces the inner surface 121b of the housing 10 located around the through hole 40. The inner facing portion 74 covers the through hole 40 when viewed along the axial direction of the main body portion 72.

  The elastic biasing member 75 is disposed between the inner facing portion 74 and the inner surface 121b of the housing 10. The elastic biasing member 75 biases the inner facing portion 74 in a direction away from the inner surface 121b of the housing 10.

  The elastic biasing member 75 is made of, for example, a rubber material having resistance to electrolytic solution. The elastic biasing member 75 is press-fitted between the inner facing portion 74 and the inner surface 121b of the housing 10, for example. Thereby, the elastic biasing member 75 develops a biasing force in a direction in which the inner facing portion 74 is moved away from the inner surface 121b of the housing 10. The elastic biasing member 75 is formed with a ventilation path 75 a communicating with the through hole 40.

  More specifically, the elastic biasing member 75 is composed of a plurality of elastic bodies that are spaced apart from each other in the circumferential direction, and a ventilation path 75a is provided between the elastic bodies adjacent to each other in the circumferential direction. ing.

  The elastic biasing member 75 is not limited to such a configuration, and may be configured by an annular elastic body provided with a plurality of ventilation paths that penetrate in the radial direction.

  The seal member 76 is disposed between the outer facing portion 73 and the outer surface 121a of the housing 10. The seal member 76 has an annular shape. The seal member 76 is disposed so as to surround the through hole 40 when viewed along the axial direction of the main body 72.

  The seal member 76 is made of a rubber material having resistance to electrolytic solution. Note that the hardness of the seal member 76 is smaller than the hardness of the elastic biasing member 75.

  When the urging force of the elastic urging member 75 acts as described above, the outer facing portion 73 of the valve body 71 receives a force so as to approach the outer surface 121a of the housing 10. Accordingly, the seal member 76 is sandwiched between the outer facing portion 73 and the outer surface 121a of the housing 10.

  As described above, the seal member 76 is sealed between the outer facing portion 73 and the outer surface 121a of the casing 10 by the biasing force of the elastic biasing member 75, thereby sealing the inside of the casing 10.

  FIG. 5 is a cross-sectional view showing a state of the gas release valve when the internal pressure of the casing of the secondary battery according to the embodiment increases. FIG. 5 shows a state of the gas release valve 70 when gas is generated from the inside of the housing 10 and the internal pressure of the housing 10 increases to reach a predetermined pressure P2. The predetermined pressure P2 is smaller than the predetermined pressure P1 at which the safety valve 30 operates.

  When the internal pressure of the housing 10 reaches the predetermined pressure P2, the gas inside the housing 10 presses the inner facing portion 74 so as to approach the inner surface 121b of the housing 10. Further, since the portion located inside the seal member 76 communicates with the inside of the housing 10 through the through hole 40 and the ventilation path 75a, the gas in the portion passes the outer facing portion 73 of the housing 10. Press in a direction away from the outer surface 121a.

  Thereby, the inner facing portion 74 moves toward the inner surface 121b of the housing 10 against the urging force. At this time, the outer facing portion 73 is separated from the seal member 76 and passes through the ventilation path 75a, the through hole 40, and the gap between the outer facing portion 73 and the seal member 76, and the inside of the housing 10 and the housing. 10 externals communicate. As a result, the gas inside the housing 10 is released from the gas release valve 70, and the internal pressure of the housing 10 decreases.

  When the internal pressure of the housing 10 decreases, the urging force of the elastic urging member 75 presses the inner facing portion 74 away from the inner surface 121b of the housing 10, and the valve body 71 moves to the original position. At this time, the seal member 76 is sandwiched between the outer facing portion 73 and the outer surface 121a of the housing 10, and the inside of the housing 10 is sealed.

  As described above, in the secondary battery according to the present embodiment, in the state where the inside of the housing 10 is sealed from the outside of the housing 10, the elastic biasing member 75 has the sealed housing. Arranged inside the body 10. For this reason, it can suppress that the elastic biasing member 75 deteriorates with the water | moisture content etc. which are contained in external air. Thereby, the fluctuation | variation of the elastic coefficient of the elastic biasing member 75 can be suppressed, As a result, it can suppress that the operating pressure of the valve body 71 varies.

  Further, by using a rubber material as the elastic urging member 75, the gas release valve 70 can be made smaller than when a spring is used. In the case where a spring is used as the elastic biasing member 75, the spring is constituted by a metal member having a resistance to electrolyte and a resin member.

  Furthermore, the operating pressure P2 of the gas release valve 70 is made smaller than the operating pressure P1 of the safety valve 30, and the gas release valve 70 is configured to be able to open and close the through hole 40, thereby reducing the pressure inside the housing 10. The operating pressure P2 or less can be suppressed. As a result, as long as the casing 10 is configured to withstand at least the pressure of the operating pressure P2, it is not necessary to increase the plate thickness of the casing 10 to withstand the pressure of the operating pressure P1. As a result, the thickness of the casing 10 can be reduced compared to the casing 10 configured to withstand the pressure of the operating pressure P1, and when the casing is configured with the same outer dimensions, the casing 10 The interior space can be widened.

  In the embodiment described above, the case where the through hole 40 is provided in the lid body 12 and the gas release valve 70 is provided in the through hole has been described as an example. Is provided at the upper part of the peripheral surface of the case body 11, and the gas release valve 70 may be provided in the through hole 40. In this case, a separate injection hole may be provided in the lid body 12.

  As described above, the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the terms of the claims, and includes meanings equivalent to the terms of the claims and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 1 Secondary battery, 10 housing | casing, 10a opening part, 11 case main body, 12 cover body, 12a, 12b insertion hole, 20 electrode body, 25 positive electrode exposed part, 26 negative electrode exposed part, 30 safety valve, 40 through-hole, 50 positive electrode Terminal, 51 Volt, 52 Positive external terminal, 53 Rivet member, 54 Insulator, 55 Gasket, 56 Current collecting electrode, 60 Negative electrode terminal, 61 Bolt, 62 Negative external terminal, 63 Rivet member, 64 Insulator, 65 Gasket, 66 Current collector Electrode, 70 Gas release valve, 71 Valve body, 72 Main body portion, 73 Outer facing portion, 74 Inner facing portion, 75 Elastic biasing member, 75a Ventilation path, 76 Seal member, 121 Thin portion, 121a Outer surface, 121b Inner surface .

Claims (1)

A housing containing a battery element therein and having a through hole;
A valve body having an outer facing portion facing the outer surface of the housing and an inner facing portion facing the inner surface of the housing, and inserted into the through hole;
An elastic biasing member that is disposed between the inner facing portion and the inner surface of the housing and biases the inner facing portion in a direction away from the inner surface of the housing;
The casing is disposed between the outer facing portion and the outer surface of the casing, and is sandwiched between the outer facing portion and the outer surface of the casing by the biasing force of the elastic biasing member. A seal member for sealing the inside of the body,
A secondary battery, wherein the elastic biasing member is formed with a ventilation path communicating with the through hole.

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