JP2015106494A - Power storage module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage module that is able to restrict slack of an immovable sealing member at an electrode terminal of a power storage device.SOLUTION: A power storage module according to one embodiment of the invention includes two power storage devices and a connecting member 2. Each power storage device has a case 10 accommodating an electrode assembly, and a pair of electrode terminals 40. Each electrode terminal 40 has: a terminal body part 41 having a first portion 42 in a flat plate form, the portion 42 facing the internal face of the case 10, and a second portion 43 in a rod form, the portion 43 extending from the first portion 42; an immovable sealing member 44 that fits on the external peripheral face 43b of the terminal body part 41 and sandwiches the case 10 in cooperation with the first portion 42; and an immovable connecting member 45 that fits on the internal face 43a of the terminal body part 41 and sandwiches a connection member 2 in cooperation with a second portion. The power storage module has an elastic member 4 provided between the immovable sealing member 44 and connecting member 2 and configured to cause elastic force F to act on the immovable sealing member 44 toward this member 44 from the connecting member 2.

Description

  The present invention relates to a power storage module including a plurality of power storage devices.

  As power storage devices, secondary batteries such as lithium ion batteries, electric double layer capacitors, and the like are known. This type of power storage device is used in the form of a power storage module connected in series using, for example, a bus bar (connection member). Patent Documents 1 to 3 disclose this type of power storage device.

  The power storage devices disclosed in Patent Documents 1 and 2 have bolt-type electrode terminals, and the case is insulated from the electrode terminals by interposing an insulating member between the electrode terminal and the case. Further, in this power storage device, an O-ring (seal member) is interposed between the electrode terminal and the case, and the case is tightened with a sealing nut (seal fixing member), thereby improving the sealing property of the case and preventing electrolyte leakage. Is preventing. Further, in this power storage device, the bus bar is inserted between the sealing nut and the bus bar nut (fixing member for connection).

  On the other hand, the power storage device disclosed in Patent Document 3 is a bolt-type electrode terminal having an electrode terminal having a fitting hole along the central axis. Similarly in this power storage device, the case is insulated from the electrode terminal by interposing an insulating member between the electrode terminal and the case. Similarly, in this power storage device, an O-ring (seal member) is interposed between the electrode terminal and the case, and tightened with a sealing nut (seal fixing member), thereby enhancing the sealing property of the case and Prevents liquid leakage. In this power storage device, the bus bar is inserted between the electrode terminal and a bus bar bolt (fixing member for connection) fitted into the fitting hole. In this power storage device, the upper surface of the sealing nut is designed to be lower than the upper surface of the electrode terminal so as not to impair electrical contact between the upper surface of the electrode terminal and the lower surface of the bus bar.

JP 2010-170920 A JP 2004-253295 A JP-A-9-92241

  However, in the power storage device disclosed in Patent Document 3, the upper surface of the sealing nut (seal fixing member) is lower than the upper surface of the electrode terminal, that is, there is a space on the upper surface of the sealing nut. The sealing nut may be loosened due to creep of the resin member or vibration applied during use. If the sealing nut is loosened, crushing of the O-ring (seal member) becomes insufficient, and the sealing performance of the case may be impaired. As a result, leakage of the electrolytic solution may occur, and the power storage device may be quickly deteriorated.

  Therefore, an object of the present invention is to provide a power storage module that can suppress loosening of a sealing fixing member in an electrode terminal of a power storage device.

  The power storage module of the present invention includes two power storage devices and a connection member that electrically connects the two power storage devices, each of the power storage devices including a case that houses an electrode assembly, and a pair of electrodes provided in the case Terminal. Each of the electrode terminals is (1) a conductive terminal body having a flat plate-like first portion facing the inner surface of the case, and a rod-like second portion extending from the first portion toward the outside of the case. A terminal body portion having an inner peripheral surface defining a hole extending along the central axis, and (2) a sealing fixing member fitted to the outer peripheral surface of the terminal main body portion. (3) a seal member inserted between at least one of the first portion of the terminal body and the case and between the seal fixing member and the case, and (4) the terminal body. A connecting fixing member for fixing the connecting member to the second portion of the terminal main body portion by fitting with the inner peripheral surface of the portion and sandwiching the connecting member in cooperation with the second portion of the terminal main body portion. (5) The sealing fixing member fixes the terminal main body portion to the case and seals the case by sandwiching the case and the sealing member in cooperation with the first portion of the terminal main body portion. (6) The power storage module includes an elastic member that is provided between the fixing member for sealing and the connecting member, and causes an elastic force to act on the fixing member for sealing from the connecting member toward the fixing member for sealing.

  According to this power storage module, the elastic member exerts an elastic force on the sealing fixing member in the electrode terminal of the power storage device, so that the sealing fixing is performed by creep of the resin member as an insulating member, vibration applied during use, or the like. It can suppress that a member loosens. As a result, it is possible to maintain the hermeticity of the case of the power storage device, reduce the occurrence of leakage of the electrolytic solution (improve safety), and suppress deterioration of the power storage device (improve life).

  The power storage module described above may include an insulating member that is inserted at least between the first portion of the terminal main body and the case, and insulates the case from the terminal main body.

  Moreover, the above-described elastic member is a dish-shaped spring, and may be provided between the terminal main body portion and the sealing fixing member and the connection member.

  The disc-shaped spring has a characteristic that the elastic force increases as the distance from the center point increases. In this regard, according to this configuration, since the elastic member is provided from the terminal main body portion to the sealing fixing member, the diameter of the elastic member can be increased even in a limited space. The acting elastic force can be increased. In addition, as described above, since the plate-like spring has a smaller elastic force as it is closer to the center point, according to this configuration, the elastic force acting on the terminal main body is small, and the electrical connection between the terminal main body and the connecting member is small. It is possible to suppress the disturbing contact.

  Moreover, the above-described elastic member may be integrated with the connection member. According to this configuration, it is easy to assemble the power storage module. On the other hand, when the elastic member is separate from the connecting member, the manufacturability of these parts is facilitated.

  According to the present invention, it is possible to suppress loosening of the sealing fixing member in the electrode terminal of the power storage device.

It is a top view which shows the electrical storage module which concerns on one Embodiment of this invention. It is sectional drawing of the electrical storage apparatus which follows the II-II line | wire shown in FIG. It is an expanded sectional view of the electrode terminal and bus bar (connection member) which follow the III-III line shown in FIG. It is a figure which shows the bus bar (connection member) shown in FIG. 1 from the electrical storage apparatus side. It is an expanded sectional view of the electrode terminal and bus bar (connection member) in the electrical storage module concerning the modification of the present invention. It is a figure which shows the bus-bar (connection member) shown in FIG. 5 from the electrical storage apparatus side. It is an expanded sectional view of the electrode terminal and bus bar (connection member) in the electrical storage module concerning the modification of the present invention. It is a figure which shows the bus-bar (connection member) shown in FIG. 7 from the electrical storage apparatus side.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a plan view showing a power storage module according to an embodiment of the present invention. The power storage module 100 shown in FIG. 1 includes four power storage devices 1 and three bus bars (connection members) 2. The power storage device 1 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, and is electrically connected in series by, for example, a metallic bus bar 2. Details of the bus bar 2 will be described later.

  FIG. 2 is a cross-sectional view of the power storage device taken along line II-II shown in FIG. The power storage device 1 illustrated in FIG. 2 includes a case 10, an electrode assembly 20, and a pair of electrode terminals 30 and 40. The case 10 is made of a metal such as aluminum and has a substantially rectangular parallelepiped space inside. The case 10 contains an electrode assembly 20 and is filled with, for example, an organic solvent-based or non-aqueous electrolyte solution 11. Further, for example, an insulating film may be provided on the inner surface of the case 10. A pair of electrode terminals, that is, a positive electrode terminal 30 and a negative electrode terminal 40 are disposed on one surface of the case 10. Details of the electrode terminals 30 and 40 will be described later.

  The electrode assembly 20 includes a plurality of positive electrodes (electrodes) 21 and a plurality of negative electrodes (electrodes) 22, and a plurality of separators disposed between the positive electrodes 21 and the negative electrodes 22. The positive electrode 21 and the negative electrode 22 are alternately stacked via separators.

  The positive electrode 21 includes, for example, a metal foil made of an aluminum foil and a positive electrode active material layer formed on both surfaces of the metal foil. The positive electrode active material layer is formed including a positive electrode active material and a binder. Examples of the positive electrode active material include composite oxide, metallic lithium, and sulfur. The composite oxide includes, for example, at least one of manganese, nickel, cobalt, and aluminum and lithium. A tab 21 a is formed on the upper edge of the positive electrode 21 corresponding to the position of the positive electrode terminal 30. The tab 21 a extends upward from the upper edge portion of the positive electrode 21 and is connected to the positive electrode terminal 30 via the conductive member 23.

  On the other hand, the negative electrode 22 has, for example, a metal foil made of copper foil and a negative electrode active material layer formed on both surfaces of the metal foil. The negative electrode active material layer is formed including a negative electrode active material and a binder. Examples of the negative electrode active material include carbon such as graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, and soft carbon, alkali metals such as lithium and sodium, metal compounds, SiOx (0.5 ≦ x ≦ 1.5 ) And the like, and boron-added carbon. A tab 22 a is formed at the upper edge of the negative electrode 22 in correspondence with the position of the negative electrode terminal 40. The tab 22 a extends upward from the upper edge portion of the negative electrode 22 and is connected to the negative electrode terminal 40 via the conductive member 24.

  In addition, as a material of a separator, the porous film which consists of polyolefin resin, such as polyethylene (PE) and a polypropylene (PP), the woven fabric or nonwoven fabric which consists of a polypropylene, a polyethylene terephthalate (PET), methylcellulose, etc. are illustrated.

  Next, the electrode terminals 30 and 40 and the bus bar 2 will be described in detail. 3 is an enlarged cross-sectional view of the electrode terminal and the bus bar taken along line III-III shown in FIG. 1, and FIG. 4 is a view showing the bus bar shown in FIG. 1 from the power storage device side. Hereinafter, the negative electrode terminal 40 will be described as a representative of the electrode terminals 30 and 40, but the positive electrode terminal 30 also has the same configuration.

  As shown in FIG. 3, the electrode terminal 40 includes a terminal bolt (terminal body portion) 41, a seal nut (seal fixing member) 44, a bus bar bolt (connection fixing member) 45, insulating members 46 and 47, an O-ring ( (Seal member) 48 is provided.

  For example, a metal is used as the material of the terminal bolt 41. The terminal bolt 41 has a substantially inverted T shape in plan view, and includes a first portion 42 and a second portion 43. The first portion 42 has a flat plate shape and is disposed in the case 10 so as to face the inner surface of the case 10. The second portion 43 has a rod shape, and extends from the first portion 42 from the inside of the case 10 to the outside through the through hole of the case 10. The second portion 43 has an inner peripheral surface 43 a that defines a hole extending along the central axis X. A thread is formed on the outer peripheral surface 43b of the second portion 43, and a seal nut 44 is fitted therein. Further, a thread groove is formed on the inner peripheral surface 43a of the second portion 43, and the bus bar bolt 45 is fitted therein.

  An insulating member 46 is arranged between the first portion 42 and the case 10 so as to go around the second portion 43, and between the second portion 43 and the case 10, and between the case 10 and the seal nut 44. Insulating member 47 is arranged so as to go around second portion 43. The case 10 is insulated from the terminal bolt 41 by these insulating members 46 and 47. An O-ring 48 is disposed between the first portion 42 and the case 10 so as to go around the second portion 43. The O-ring 48 may be arranged between the seal nut 44 and the case 10 so as to go around the second portion 43.

  The seal nut 44 fixes the terminal bolt 41 to the case 10 by sandwiching the case 10, the insulating members 46 and 47, and the O-ring 48 in cooperation with the first portion 42 of the terminal bolt 41. Further, the case 10 is sealed by the tightening action of the seal nut 44 and the elastic characteristics of the O-ring.

  The bus bar bolt 45 sandwiches the bus bar 2 in cooperation with the second portion 43 of the terminal bolt 41, so that the bus bar 2 is connected to the upper surface of the second portion 43 of the terminal bolt 41 (the first portion 42 in the second portion 43 is different from the first portion 42. Fix to the opposite side. The upper surface of the seal nut 44 (so as not to impair the electrical contact between the upper surface of the second portion 43 of the terminal bolt 41 and the lower surface of the bus bar 2 (the surface of the bus bar 2 facing the second portion 43). The surface of the seal nut 44 facing the bus bar 2 is designed to be lower than the upper surface of the second portion 43 of the terminal bolt 41.

  As shown in FIGS. 3 and 4, the bus bar 2 has a plate-like main body 3. The main body 3 has a through hole 3 a at a position corresponding to the bus bar bolt 45. An elastic part (elastic member) 4 is provided on the lower surface of the main body 3 of the bus bar 2 (the surface of the main body 3 on the terminal bolt 41 and the seal nut 44 side). That is, the elastic portion 4 is provided between the terminal bolt 41 and the seal nut 44 and the main body portion 3 of the bus bar 2.

  The elastic part 4 has an elastic force, a part thereof is joined to the lower surface of the main body part 3 of the bus bar 2, and one end abuts against the seal nut 44. The elastic part 4 of the present embodiment is, for example, a disc spring made of the same metal material as that of the main body 3 and generating an elastic force by a curved shape so as to be convex toward the main body side. Further, the elastic part 4 of the present embodiment will be described in detail. The dish-like elastic part 4 has a through hole 4a through which the bus bar bolt 45 is inserted, and the through hole 3a of the main body part 3 and the elastic part 4 The lower surface of the main body 3 of the bus bar 2 and the portion around the through hole 4a are joined so that the through hole 4a communicates. The elastic part 4 is formed so as to move away from the lower surface of the main body 3 as it goes from the portion joined to the lower surface of the main body 3 toward the outer peripheral edge, and the outer peripheral edge comes into contact with the seal nut 44.

  In the present embodiment, the elastic portion 4 is integrated with the main body portion 3. For example, the main body part 3 and the elastic part 4 may be integrally molded at the time of molding, or may be bonded after being molded separately.

  Thus, according to the power storage module 100 of the present embodiment, the seal nut (seal fixing member) 44 in the electrode terminals 30 and 40 of the power storage device 1 is provided by the elastic portion (elastic member) 4 in the bus bar (connection terminal) 2. Since the elastic force F acts on the upper surface of the resin member from the bus bar (connecting member) 2 toward the seal nut (seal fixing member) 44, creep of the resin member as the insulating members 46 and 47, vibration applied during use, etc. Thus, the loosening of the seal nut (seal fixing member) 44 can be suppressed. As a result, the crushing of the O-ring (seal member) 48 can be sufficiently maintained, the sealing property of the case 10 of the power storage device 1 can be maintained, and the occurrence of leakage of the electrolytic solution 11 can be reduced. (Improvement in safety) and deterioration of the power storage device 1 can be suppressed (improvement in life).

  By the way, a plate-shaped spring has the characteristic that the elastic force is so large that it is far from the center point (center of the through hole 4a). In this regard, according to the power storage module 100 of the present embodiment, the elastic portion (elastic member) 4 extends from the upper surface of the second portion 43 of the terminal bolt (terminal main body portion) 41 to the upper surface of the seal nut (sealing fixing member) 44. Therefore, even in a limited space, the diameter of the elastic portion (elastic member) 4 can be increased and the elastic force F acting on the upper surface of the seal nut (sealing fixing member) 44 can be increased. Can do. Further, as described above, since the plate-like spring has a smaller elastic force as it is closer to the center point, according to the power storage module 100 of the present embodiment, the upper surface of the second portion 43 of the terminal bolt (terminal body portion) 41 is arranged. The acting elastic force is small, and it is possible to suppress the electrical contact between the upper surface of the second portion 43 of the terminal bolt (terminal body portion) 41 and the lower surface of the bus bar (connecting member) 2.

  Further, according to the power storage module 100 of the present embodiment, the elastic portion (elastic member) 4 is integrated with the bus bar (connecting member) 2, so that the assembly work of the power storage module is easy.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the features of the present invention can be applied to a power storage module including two or more power storage devices and one or more bus bars (connection members).

  The features of the present invention can also be applied to a power storage module that does not include the insulating members 46 and 47. In this case, an insulating coating may be applied to at least one of the portion of the case 10 facing the terminal bolt 41 and the portion of the terminal bolt 41 facing the case 10. Further, at least one of the portion of the case 10 facing the seal nut 44 and the portion of the seal nut 44 facing the case 10 may be provided with an insulating coating.

  The elastic member of the present invention is not limited to this embodiment. For example, in the present embodiment, a disk-shaped spring, particularly a curved disk spring, is exemplified as the elastic member. However, as the disk-shaped spring, a portion in contact with the upper surface of the terminal bolt (terminal body portion) is flat, and A diaphragm spring having a flat portion between the upper surface of the terminal bolt and the portion in contact with the seal nut may be used (see FIGS. 5 and 6). Further, in the present embodiment, the elastic member is illustrated as being provided over the upper surface of the terminal bolt (terminal body portion) and the upper surface of the seal nut (fixing member for sealing). The fixing member may be provided only on the upper surface (see FIGS. 7 and 8).

  Moreover, in this embodiment, although the spring which generate | occur | produces an elastic force in shape using a flexible material was illustrated as an elastic member, an elastic member generates an elastic force using the material which has elasticity. It may be rubber or the like. In this case, the elastic member is preferably provided only on the upper surface of the seal nut (fixing member for sealing) so as not to hinder the electrical contact between the terminal main body and the connecting member.

  In the present embodiment, the elastic member is integrated with the connecting member. However, the elastic member may be separate from the connecting member. For example, the separate elastic member may be the same member as described above, or may be an existing member such as a spring washer. In this case, the manufacturability of these parts is easy.

  Further, in the present embodiment, the power storage module including the power storage device having the stacked electrode assembly is illustrated, but the feature of the present invention is the power storage module including the power storage device having various electrode assemblies such as a winding type. It is also applicable to.

  In the present embodiment, the power storage module including the secondary battery is illustrated as the power storage device. However, the features of the present invention can be applied to a power storage module including various power storage devices such as an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 100 ... Power storage module, 1 ... Power storage device, 2 ... Bus bar (connection member), 3 ... Main part of bus bar, 4 ... Elastic part (elastic member), 10 ... Case of power storage device, 11 ... Electrolyte, 20 ... Electrode set Solid, 21 ... Positive electrode (electrode), 21a ... Tab, 22 ... Negative electrode (electrode), 22a ... Tab, 23, 24 ... Conductive member, 30 ... Positive electrode terminal (electrode terminal), 40 ... Negative electrode terminal (electrode terminal), 41 ... Terminal bolt (terminal body part), 42 ... First part of terminal bolt, 43 ... Second part of terminal bolt, 43a ... Inner peripheral surface of terminal bolt, 43b ... Outer peripheral surface of terminal bolt, 44 ... Seal nut (seal Fixing member), 45 ... busbar bolt (fixing member for connection), 46, 47 ... insulating member, 48 ... O-ring (seal member).

Claims (4)

A power storage module comprising two power storage devices and a connection member that electrically connects the two power storage devices,
Each of the power storage devices has a case for accommodating an electrode assembly, and a pair of electrode terminals provided in the case,
Each of the electrode terminals is
A conductive terminal body having a flat plate-like first portion facing the inner surface of the case, and a rod-like second portion extending from the first portion toward the outside from the inside of the case, The second portion has an inner peripheral surface defining a hole extending along a central axis;
A fixing member for sealing that fits with the outer peripheral surface of the terminal main body,
A seal member inserted between at least one of the first portion of the terminal body portion and the case and between the sealing fixing member and the case, and for sealing the case;
The connection member is fixed to the second part of the terminal body part by fitting with the inner peripheral surface of the terminal body part and sandwiching the connection member in cooperation with the second part of the terminal body part. A fixing member for connection,
The sealing fixing member fixes the terminal body portion to the case and seals the case by sandwiching the case and the sealing member in cooperation with the first portion of the terminal body portion,
An elastic member that is provided between the sealing fixing member and the connection member, and causes an elastic force to act on the sealing fixing member from the connection member toward the sealing fixing member;
Power storage module.   The power storage module according to claim 1, further comprising an insulating member that is inserted between at least the first portion of the terminal main body portion and the case and insulates the case from the terminal main body portion.   The power storage module according to claim 1, wherein the elastic member is a dish-shaped spring, and is provided between the terminal main body portion, the sealing fixing member, and the connection member.   The power storage module according to claim 1, wherein the elastic member is integrated with the connection member.

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