JP2015043282A - Storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit deposition of a positive-electrode active material, such as lithium, on a battery container and suppress a short circuit current flowing from the battery container side to the exterior case side when a short circuit occurs between the battery container and a metal exterior case enclosing the battery container.SOLUTION: A secondary battery 1 includes: a metal case 40 which stores a power generation element 10 including a positive electrode plate and a negative electrode plate; a positive electrode terminal 60P which penetrates through the case 40 and is electrically connected with the positive electrode plate; a negative electrode terminal 60N which penetrates through the case 40 and is electrically connected with the negative electrode plate; a positive electrode side seal member 70P which seals a space between the case 40 and the positive electrode terminal 60P; and a negative electrode side seal member 70N which seals a space between the case 40 and the negative electrode terminal 60N. One of the positive electrode side seal member 70P and the negative electrode side seal member 70N is formed by a conductive material having a resistance value higher than that of the case 40 and the other is formed by an insulative material.

Description

  The present invention relates to a technique for suppressing a short-circuit current flowing between an outer case and a battery container.

  One storage element is a lithium ion secondary battery. Patent Document 1 listed below discloses a technique for preventing lithium deposition on the battery container by setting the battery container of the lithium ion secondary battery to the same potential as the positive electrode terminal.

JP 2008-186591 A

  However, in the structure of Patent Document 1, it is necessary to add a resistance element that connects the battery container and the positive electrode terminal, and the number of parts increases. In addition, when the battery container is set to the same potential as the positive electrode terminal without using a resistance element, when the battery container is short-circuited with a metal outer case surrounding it, a large short-circuit current flows from the battery container side to the outer case side, It was a challenge to suppress it.

  The electricity storage device disclosed in this specification includes a metal battery container that houses a power generation element including a positive electrode plate and a negative electrode plate, and penetrates the battery container and is electrically connected to the positive electrode plate. A positive electrode terminal, a negative electrode terminal penetrating the battery container and electrically connected to the negative electrode plate, a positive electrode side sealing member that seals between the battery container and the positive electrode terminal, and the battery A negative electrode side sealing member that seals between the container and the negative electrode terminal, and one of the positive electrode side sealing member and the negative electrode side sealing member is a conductive material having a larger resistance value than the battery container. The other is an insulating material.

  In this power storage element, both the positive electrode side sealing member and the negative electrode side sealing member material are elastic materials.

  In this power storage element, the positive electrode side sealing member and the negative electrode side sealing member are different in material color.

  In this power storage element, the positive electrode side sealing member is a conductive material having a larger resistance value than the battery container, and the negative electrode side sealing member is an insulating material.

  In this power storage element, the conductive material is a conductive rubber, and the insulating material is an insulating rubber.

  According to the invention disclosed by this specification, precipitation of active materials, such as lithium, with respect to a battery container can be suppressed. Furthermore, when the battery case is short-circuited with the metal outer case surrounding it, it is possible to suppress a short-circuit current flowing from the battery case side to the outer case side.

The perspective view of the secondary battery in one embodiment Exploded perspective view of secondary battery Side view of power generation element Exploded perspective view of lid, positive electrode terminal, positive electrode side sealing member, positive electrode current collector AA line sectional view of FIG. The top view which shows the state which accommodated the secondary battery in the outer case The schematic diagram which shows the seal structure around the terminal of the secondary battery in other embodiment.

(Outline of this embodiment)
First, an outline of the electricity storage device of this embodiment will be described. In this power storage element, since either the positive electrode terminal or the negative electrode terminal is electrically connected to the battery container, the potential of the battery container is approximately the same as that of the positive electrode terminal or the negative electrode terminal. Therefore, it can suppress that an active material precipitates in a battery container. In addition, a seal member is used for electrical connection between the battery case and the terminal. Therefore, it is possible to make the potential of the battery container almost the same as that of the terminal only by exchanging the parts (changing the seal member), and the number of parts does not increase. In addition, the sealing member that connects the battery container and the terminal has a larger resistance value than the battery container. Therefore, even if the battery case is short-circuited with a metal outer case or the like surrounding the battery case, it is possible to suppress a short-circuit current flowing through the outer case via the battery case.

  In this power storage element, since the sealing member is made of an elastic material, the sealing performance is high and leakage of the electrolyte can be reliably prevented. Further, the impact and vibration applied to the positive terminal and the negative terminal can be reduced. In addition, both of the pole seal members are made of an elastic material. As a result, the response to the stress of the bipolar terminals becomes equal, and the reliability as the power storage element is improved.

  In this power storage device, the material of the seal members of both electrodes is different. Therefore, a manufacturing worker or a user can easily identify the positive electrode and the negative electrode based on the difference in color.

  In this power storage element, since the battery container and the positive electrode terminal are electrically connected, the potential of the battery container is substantially the same as that of the positive electrode terminal. Therefore, it can suppress that positive electrode active materials, such as lithium, precipitate on a battery container.

  In this power storage element, the conductive material is a conductive rubber, and the insulating material is an insulating rubber. If it is rubber, it is inexpensive and has cost merit.

<Embodiment>
1. Configuration of Secondary Battery The secondary battery 1 is a lithium ion battery that can be repeatedly charged and discharged. The secondary battery 1 is mounted on, for example, an electric vehicle or a hybrid vehicle, and supplies power to a power source that operates with electric energy. Note that the secondary battery 1 is an example of a “storage element”.

  As shown in FIGS. 1 and 2, the secondary battery 1 includes a power generation element 10, an insulating film 35, a case 40, a positive electrode terminal 60P, a negative electrode terminal 60N, a positive electrode current collector 90P, and a negative electrode current collector 90N. A side seal member 70P and a negative electrode side seal member 70N are provided (see FIGS. 4 and 5). In the following description, the lateral width direction of the case 40 is the X direction, the depth direction of the case 40 is the Y direction, and the vertical direction is the Z direction. The case is an example of a “battery container”.

  The power generation element 10 includes a positive electrode plate 12P, a negative electrode plate 12N, and a separator 15. The positive electrode plate 12P has a positive electrode active material layer formed on the surface of a strip-shaped aluminum foil, and the negative electrode plate 12N has a negative electrode active material layer formed on the surface of a strip-shaped copper foil. The power generation element 10 is configured to be wound in a flat shape with the separator 15 sandwiched between the positive electrode plate 12P and the negative electrode plate 12N (see FIG. 3). In addition, the positive electrode current collector foil 13P in which the aluminum foil is exposed without forming the positive electrode active material layer is formed at one edge of the positive electrode plate 12P in the X direction (in this example, the right edge in FIG. 2). Then, the negative electrode current collector foil 13N in which the copper foil is exposed without forming the negative electrode active material layer is formed on the other edge part in the X direction of the negative electrode plate 12N (the left edge part in FIG. 2 in this example). Has been.

  As shown in FIGS. 1 and 2, the case 40 includes a case main body 41 and a lid body 50. The case main body 41 has a box shape with an upper surface opened, and is made of metal. In addition, although aluminum and stainless steel can be applied as the material of the case main body 41, it is preferable to use aluminum. The reason is that it is difficult to corrode when the case body 41 is set to the same potential as the positive electrode terminal 60P. The insulating film 35 insulates between the power generation element 10 and the case body 41 and has a box shape that can surround the power generation element 10. The case main body 41 accommodates the power generation element 10 together with the insulating film 35 and is further filled with an electrolytic solution.

  The lid 50 is made of a conductive material and is made of metal. In addition, although aluminum and stainless steel can be applied as the material of the lid 50, it is preferable to use aluminum. The reason is that it is difficult to corrode when the lid 50 is set to the same potential as the positive electrode terminal 60P. The lid 50 has a substantially rectangular shape as a whole, and has substantially the same shape as the opening 41 </ b> A of the case 41. The lid 50 is joined to the case body 41 so as to close the opening 41 </ b> A, and has a structure for sealing the case body 41.

  The positive electrode terminal 60P and the negative electrode terminal 60N are terminals for electrical connection with electric devices and other secondary batteries, and the secondary battery 1 is disposed at one end side in the X direction of the lid 50 (right side in this example). The positive electrode terminal 60P is arranged, and the negative electrode terminal 60N is arranged on the other end side in the X direction (left side in this example).

  As shown in FIG. 4, the positive electrode terminal 60 </ b> P includes a metal plate 61, a metal bolt 65, and a metal rivet (coupling member) 67. The plate 61 is a flat plate that is long in the X direction, and is formed with a first through hole 62 through which the screw portion of the bolt 65 passes and a second through hole 63 through which the rivet 67 passes.

  The bolt 65 is for attaching a terminal (not shown) provided on a harness connected to the electric device or a bus bar (reference numeral 140 in FIG. 6) for electrically connecting the secondary batteries to each other. It penetrates the through hole 62 upward and protrudes to the upper surface side of the plate 61.

  The rivet 67 penetrates the second through hole 63 of the plate 61 downward, and further, the through hole 76 of the outer seal member 71, the through hole 52 of the lid 50, the through hole 82 of the inner seal member 81P, the positive electrode current collector 90P. The through holes 92 of the main body 91 are sequentially passed. Then, by crimping the tip of the rivet 67 protruding downward from the main body 91 of the positive electrode current collector 90P, the plate 61 with the bolts 65 attached thereto is fixed to the upper surface side of the lid 50. The positive electrode current collector 90P is fixed to the lower surface side.

  The positive electrode current collector 90P electrically connects the positive electrode terminal 60P and the positive electrode plate 12P. The positive electrode current collector 90P is made of, for example, an aluminum alloy plate and includes a main body 91 and a positive electrode leg 95 as shown in FIG.

  The main body 91 is a substantially trapezoidal flat plate and is disposed on the lower surface side of the lid 50. A through hole 92 is formed in the main body 91, and the rivet 67 of the positive terminal 60P is vertically penetrated.

  The positive electrode leg portion 95 extends from the end edge of the main body portion 91 in a downward direction corresponding to the inside of the case. The positive electrode leg portion 95 is ultrasonically welded with the positive electrode current collector foil 13P sandwiched by a clip 30P on the positive electrode side made of an aluminum alloy. Thus, the positive electrode current collector 90P is electrically connected to the positive electrode plate 12P. The positive electrode current collector 90P has a sufficient thickness so that a large current capacity can be obtained.

  The positive seal member 70P seals the periphery of the through hole 52 formed in the lid body 50 so that the internal electrolyte does not leak out of the case 40. The outer seal member 71P, An inner seal member 81P.

  The outer seal member 71P is made of an elastic material, specifically rubber, and is slightly larger than the plate 61 as shown in FIG. The outer seal member 71P is inserted between the lid 50 and the plate 61. A flange 72 is formed on the outer periphery of the outer seal member 71P over the entire periphery, and surrounds the periphery of the plate 61.

  In addition, the outer seal member 71 is formed with a housing portion 74 that houses the head of the bolt 65 and a through hole 76 through which the rivet 67 passes. A circular flange 78 is formed at the hole edge of the through hole 76. The circular flange 78 is fitted in the through hole 52 formed in the lid body 50. The rivet 67 passes through the inside of the circular flange 78 and is not in contact with the through hole 52 of the lid 50.

  The outer seal member 71P is closely contacted between the lower surface of the plate 61 and the upper surface of the lid 50 to seal between the two, and is also closely contacted between the through hole 52 of the lid 50 and the rivet 67. , Seal between the two.

  Further, the outer seal member 71P is made of conductive rubber (a mixture of conductive raw material such as natural rubber or synthetic rubber with conductive carbon black or metal powder). Since the outer seal member 71P is made of a conductive material, the case 40 and the positive electrode terminal 60P are electrically connected to each other, so that the case 40 can be set to substantially the same potential as the positive electrode terminal 60P as described later. The resistance value of the outer seal member 71P is preferably larger than the resistance value on the case 40 side. In this example, the resistance value of the case 40 is “0.1” Ω or less, whereas the resistance value of the outer seal member 71P is The resistance value is set to a value larger than “0.1” Ω, specifically about 500Ω. The reason why the resistance value of the outer seal member 71P is made higher than the case 40 side is that the short-circuit current can be suppressed as described later. In addition, as a numerical example of the resistance value of the outer seal member 71P, “100” Ω to “10000” Ω is preferable, and “100” Ω to “1000” Ω is more preferable.

  The inner seal member 81P is made of an insulating elastic material, specifically, an insulating rubber, and has the same shape as the main body 91 of the positive electrode current collector 90P. As shown in FIG. 5, the inner seal member 81P is inserted between the lid 50 and the main body 91 of the positive electrode current collector 90P. The inner seal member 81P is in close contact with the lower surface of the lid 50 and the upper surface of the positive electrode current collector 90P, and seals between the two. Further, the inner seal member 81P is fitted on the outer periphery of the rivet 67 without a gap, and seals around the rivet 67.

  Similarly to the positive electrode terminal 60P, the negative electrode terminal 60N includes a metal plate 61, a metal bolt 65, and a metal rivet 67. The bolt 65 is for attaching a terminal (not shown) provided on a harness connected to the electrical device or a bus bar for electrically connecting the secondary batteries, passes through the plate 61 upward, and is on the upper surface side of the lid body 50. Protruding. The rivet 67 penetrates the plate 61 downward, and, like the rivet 67 on the positive electrode terminal side, the plate 61 on which the bolt 65 is attached is fixed to the upper surface side of the lid 50, and the negative electrode current collector 90N is fixed to the lid 50. The function to fix to the lower surface side of the.

  The negative electrode current collector 90N is for electrically connecting the negative electrode terminal 60N and the negative electrode plate 12N. The negative electrode current collector 90N is made of, for example, a copper alloy plate, and has a main body 91 and a negative electrode leg 95 similar to the positive electrode current collector 90P. The main body 91 is a substantially trapezoidal flat plate and is disposed on the lower surface side of the lid 50. The negative electrode leg 95 is ultrasonically welded in a state where the negative electrode current collector foil 13N is sandwiched between the negative electrode side clip 30N made of a copper alloy. Accordingly, the negative electrode terminal 60N is electrically connected to the negative electrode plate 12N.

  Similarly to the positive electrode side seal member 70P, the negative electrode side seal member 70N seals the periphery of the through hole 52 formed in the lid 50 so that the internal electrolyte does not leak to the outside of the case 40. And includes an outer seal member 71N and an inner seal member 81N.

  The outer seal member 71N is made of an insulating elastic material, specifically, an insulating rubber, and has a shape that is slightly larger than the plate 61. The outer seal member 71N is inserted between the lid 50 and the plate 61 in the same manner as the outer seal member 71P on the positive electrode side. The outer seal member 71N has the same structure as the outer seal member 71P on the positive electrode side. The outer seal member 71N seals between the lower surface of the plate 61 and the upper surface of the lid body 50 with no gap therebetween, and the through hole 52 of the lid body 50. And the rivet 67 are in close contact with each other, and the gap between the two is sealed.

  Moreover, the outer seal members 71P and 71N on the positive electrode side and the negative electrode side are set to have different colors. Specifically, the outer seal member 71P on the positive electrode side is “red”, whereas the outer seal member 71N on the negative electrode side is “black”. Thus, by changing the colors of the outer seal members 71P and 71N, the manufacturing operator and the user can easily identify the positive electrode and the negative electrode from the difference in color.

  The inner seal member 81N is made of an insulating elastic material, specifically, insulating rubber, and has the same shape as the main body 91 of the negative electrode current collector 90N. Like the inner seal member 71P on the positive electrode side, the inner seal member 81N is inserted between the lid 50 and the main body 91 of the negative electrode current collector 90N, and the lower surface of the lid 50 and the negative electrode current collector 90N It fulfills the function of tightly contacting the upper surface of the main body without any gap and sealing between the two. Further, the inner seal member 81N is fitted to the outer periphery of the rivet 67 without a gap, and seals around the rivet 67.

  In the secondary battery 1, as described above, since the outer seal member 71P is conductive and the inner seal member 71N is insulative, only the positive electrode terminal 60P is electrically connected to the case 40, and the negative electrode The terminal 60N is insulated. Therefore, the potential of the case 40 can be made substantially the same as that of the positive electrode terminal 60P.

2. Effect explanation Since the potential of the case 40 is set to the same potential as the positive electrode terminal 60P, the secondary battery 1 does not attract lithium ions, which are cations, to the case 40 side. Therefore, lithium deposition on the case 40 can be suppressed.

  In addition, an outer seal member 71P used for sealing is used for electrical connection between the case 40 and the positive terminal 60P. Therefore, it is possible to make the potential of the case 40 substantially the same as that of the positive terminal 60P only by exchanging parts (exchanging the outer seal member 71P), and the number of parts does not increase.

  Further, as a method of bringing the case 40 to the same potential as the positive electrode terminal 60P, there is a method of bringing the positive electrode terminal 60P into direct contact with the case 40. However, when the positive electrode terminal 60P is brought into direct contact with the case 40, when the case 40 is short-circuited to the metal outer case 130 surrounding the case 40 as shown in FIG. 40 may cause a large short-circuit current to flow to the outer case 130 side.

  In this regard, in the present secondary battery 1, the resistance value of the outer seal member 71 </ b> P is larger than that of the case 40. Therefore, even when the case 40 is short-circuited with the metal outer case 130 surrounding the case 40, the short-circuit current can be suppressed by the resistance of the outer seal member 71P.

Further, since the outer seal members 71P and 71N are made of an elastic material, the sealing performance is high, and leakage of the electrolyte can be reliably prevented. Further, vibration and impact applied to the positive terminal 60P and the negative terminal 60N can be reduced. In addition, both outer seal members 71P and 71N of both poles are made of an elastic material. Therefore, the response to the stress of the bipolar terminals 60P and 60N becomes equal, and the reliability as the secondary battery 1 is improved. In this example, the outer seal members 71P and 71N are made of rubber. Rubber has the advantage of being cheaper than other materials.
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, a lithium ion secondary battery is illustrated as an example of a power storage element. However, the present invention is not limited to this, and is a secondary battery other than a lithium ion secondary battery, a capacitor with an electrochemical phenomenon, or the like. Also good.

  (2) In the above embodiment, the positive side outer seal member 71P is made conductive and the negative side outer seal member 71N is made insulating. However, the positive side inner seal member 81P is made conductive and the negative side inner seal member is made conductive. 81N may be insulative. In addition, when the inner seal member 81P on the positive electrode side is made conductive and the inner seal member 81N on the negative electrode side is made insulating, it is preferable to change the color of the seal members 81P and 81N between the two electrodes. By doing so, the manufacturing operator can easily identify the positive electrode and the negative electrode from the difference in color.

  (3) In the above-described embodiment, an example in which the seal member 70 includes the outer seal member 71 and the inner seal member 81 has been described. However, the seal member 70 does not necessarily need to be divided into the outer and the inner. If the positive electrode side seal member 250P is “conductive” and the negative electrode side seal member 250N is “insulating”, the seal members 250P and 250N of the respective electrodes as in the secondary battery 200 shown in FIG. It may be a single configuration.

  (4) In the above embodiment, the outer seal member 71 and the inner seal member 81 are made of rubber, but the material of these seal members may be an elastic material other than rubber, such as a thermoplastic elastomer. Moreover, even if it is other than an elastic material, what is necessary is just to be able to fulfill | perform the function which seals between the case 40 and the terminal 60, for example, it is good also as a thin plate-shaped gasket which consists of synthetic resins. However, as a material, it is necessary to be a material (for example, synthetic resin) which can select electroconductivity and insulation.

  (5) In the above embodiment, an example in which the entire outer seal member 71P is made of a conductive material has been shown. However, it is sufficient if the case 40 and the positive electrode terminal 60P can be electrically connected, for example, insulation having a sealing function. The structure which forms a conductive member in a part of conductive base material, and electrically connects both may be sufficient.

  (6) In the above embodiment, the entire surface of the case 40 is a metal surface. Even if the surface of the case 40 is partially covered with an insulating material, if the metal surface is exposed, there is a possibility of short-circuiting with the outer case 130. Therefore, the surface of the case 40 is made of an insulating material. The present technology is effective even when a portion is covered.

  (7) In the above embodiment, the example has been described in which the outer seal member 71P is conductive and the inner seal member 71N is insulative, so that the potential of the case 40 is substantially the same as that of the positive electrode terminal 60P. In addition, for example, when the positive terminal 60P is a reference of potential, such as when the positive terminal 60P is “0” V and the negative terminal 60N is “−4” V, the outer seal member 71P is made insulative and the inner seal is sealed. By making the member 71N conductive, the potential of the case 40 may be substantially the same as that of the negative electrode terminal 60N. As described above, when the case 40 is set to the same potential as the negative electrode terminal 60N, a short circuit between the case 40 and the external case 130 causes a short-circuit current to flow from the external case 130 side to the secondary battery 1 through the case 40. However, the short circuit current can be suppressed by the resistance of the inner seal member 71N. When the case 40 is set to the same potential as the negative electrode terminal 60N, the following effects can be obtained. If the anion in the electrolytic solution is distributed on the surface of the case 40, the anion in the electrolytic solution in the power generation element 10 is unevenly distributed on the surface of the case 40, and the charge / discharge reaction may not easily occur. Therefore, if the case 40 is set to the same potential as the negative electrode terminal 60N so that anions are not distributed on the surface of the case 40, transient deterioration which becomes a problem when charging / discharging at a high rate is unlikely to occur. It is possible to prevent temporary capacity deterioration. Further, since the anion is prevented from being attracted to the case 40, the deposition of the negative electrode active material on the case 40 can be prevented.

1: secondary battery, 10: power generation element, 40: case, 50: lid, 60P: positive electrode terminal, 60N: negative electrode terminal, 70P: positive electrode side seal member, 70N: negative electrode side seal member, 71P: outer seal member (positive electrode) ), 71N: outer seal member (negative electrode), 90P: positive electrode current collector, 90N: negative electrode current collector

Claims (5)

A storage element,
A metal battery container containing a power generation element including a positive electrode plate and a negative electrode plate;
A positive electrode terminal penetrating the battery container and electrically connected to the positive electrode plate;
A negative electrode terminal penetrating the battery container and electrically connected to the negative electrode plate;
A positive seal member that seals between the battery container and the positive terminal;
A negative electrode side sealing member that seals between the battery container and the negative electrode terminal,
One of the positive electrode side seal member and the negative electrode side seal member is a conductive element having a resistance value larger than that of the battery container, and the other is an insulating material. The power storage device according to claim 1,
The positive electrode side sealing member and the negative electrode side sealing member are both power storage elements made of an elastic material. The electric storage device according to claim 1 or 2,
The power storage element according to claim 1, wherein the positive electrode side sealing member and the negative electrode side sealing member are different in material color. It is an electrical storage element as described in any one of Claims 1-3, Comprising:
The positive electrode side seal member is a conductive material having a larger resistance value than the battery container, and the negative electrode side seal member is an insulating material. It is an electrical storage element as described in any one of Claims 1-4, Comprising:
The power storage element, wherein the conductive material is a conductive rubber, and the insulating material is an insulating rubber.

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