Electric storage cell

Abstract

To provide a simple safety mechanism.SOLUTION: An electric storage cell including a case, electrode terminals, and a power generating element, wherein the case houses the power generating element, the electrode terminals include a positive electrode terminal and a negative electrode terminal, the electrode terminals have a member contact part that contacts another member, and at least one of the positive electrode terminal and the negative electrode terminal has a recessed part in the member contact part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2017-16734 discloses a power storage device that includes a current interruption mechanism as a safety mechanism to prevent an abnormality occurring in the power storage device from being transmitted to other power storage devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-16734 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the current interruption mechanism described in Patent Document 1 has a complex structure, and a simpler safety mechanism is desired.

[0005] An object of the present disclosure is to provide a simple safety mechanism. [Means for solving the problem]

[0006] The technical configuration and effects of the present disclosure will be described below. However, the mechanism of action includes speculation. The mechanism of action does not limit the technical scope of the present disclosure.

[0007] [1] A storage cell including a case, electrode terminals, and a power generating element, the case accommodates the power generating element, the electrode terminals include a positive terminal and a negative terminal; the electrode terminal has a member contact portion that comes into contact with another member, At least one of the positive electrode terminal and the negative electrode terminal has a recess in the member contact portion.

[0008] At least one of the positive electrode terminal and the negative electrode terminal has a recess in a member contact portion that comes into contact with another member. By having a recess in the member contact portion of the electrode terminal, the contact area between the electrode terminal and the other member is reduced, so that when an external force such as an impact is applied to the electrode terminal, the electrode terminal and the other member are more likely to separate. As a result, the electrode terminal and the other member are separated, and the conductive path can be interrupted.

[0009] [2] The storage cell according to [1], wherein the positive electrode terminal and the negative electrode terminal have recesses at the member contact portions.

[0010] [3] The energy storage cell according to [1] or [2], wherein the other member is a bus bar.

[0011] [4] The storage cell according to any one of [1] to [3], wherein the electrode terminals are made of a conductive ceramic material.

[0012] [5] The storage cell according to any one of [1] to [4], wherein the electrode terminals are configured to face outward from the vehicle when the storage cell is mounted on the vehicle.

[0013] Hereinafter, one embodiment of the present disclosure (hereinafter, may be abbreviated as "the present embodiment") will be described. However, this embodiment does not limit the technical scope of the present disclosure. This embodiment is illustrative in all respects. This embodiment is non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is also intended from the beginning that any configuration may be extracted from this embodiment and arbitrarily combined. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing an example of a storage cell according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of a storage cell according to this embodiment. [Figure 3] FIG. 3 is a schematic plan view showing an example of the vicinity of an electrode terminal in this embodiment. [Figure 4] FIG. 4 is a schematic plan view showing another example of the vicinity of the electrode terminal in this embodiment. [Figure 5] FIG. 5 is a schematic plan view showing an example in which the power storage cell of this embodiment is mounted on a vehicle. [Figure 6] FIG. 6 is a schematic plan view showing another example in which the power storage cell according to this embodiment is mounted on a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Terms and phrases> "Comprise," "include," "have," and variations thereof are open-ended terms. Open-ended terms may or may not include additional elements in addition to the required elements. "Consisting of" is a closed term. However, even a structure expressed in closed terminology may include additional elements that are normally associated with the technology or that are unrelated to the technology in question. "Consisting essentially of..." is a semi-closed term. Semi-closed terminology allows for the addition of elements that do not substantially affect the basic and novel characteristics of the technology in question.

[0016] Expressions such as "may" and "may" are used in the permissive sense, meaning "to have the possibility," rather than in the obligatory sense, meaning "to have to."

[0017] Geometric terms should not be interpreted in a strict sense. Examples of geometric terms include "parallel," "perpendicular," and the like. For example, directions, angles, distances, and the like may be displaced relative to one another as long as substantially the same or similar functions are obtained. Geometric terms may include, for example, tolerances, errors, and the like in design, work, manufacturing, and the like. The dimensional relationships in each figure may not match the actual dimensional relationships. The dimensional relationships in each figure may be changed to aid the reader's understanding. For example, length, width, thickness, and the like may be changed. Some components may be omitted.

[0018] Elements described in the "singular" may also include the plural unless otherwise specified. For example, an electrode terminal may refer to a plurality of electrode terminals (electrode terminal groups).

[0019] "Storage cell" refers to a rechargeable battery. The storage cell may be, for example, a lithium-ion battery. The storage cell may contain, for example, a liquid electrolyte, a gel electrolyte, or a solid electrolyte.

[0020] "Electrode" is a general term for positive and negative electrodes. Similarly, for example, "electrode terminal" is a general term for positive and negative terminals. "Current collecting tab" is a general term for positive and negative current collecting tabs.

[0021] A "power storage module" includes a plurality of power storage cells. A power storage module is an assembly in which a plurality of power storage cells are connected. A "power storage device" includes a plurality of power storage modules. A power storage device is an assembly in which a plurality of power storage modules are connected.

[0022] <Energy storage cell> FIG. 1 is a schematic diagram showing an example of a storage cell in this embodiment. FIG. 2 is a schematic cross-sectional view showing an example of a storage cell in this embodiment. FIG. 3 is a schematic plan view showing an example of the vicinity of an electrode terminal in this embodiment. FIG. 4 is a schematic plan view showing another example of the vicinity of an electrode terminal in this embodiment. In FIGS. 3 and 4, the vicinity of the positive electrode terminal 82a is shown. Although not shown, the vicinity of the negative electrode terminal 83a may also have a structure similar to that of the positive electrode terminal 82a.

[0023] The energy storage cell 1 includes a case 80, electrode terminals, and a power generating element 50. The case 80 houses the power generating element 50. The electrode terminals include a positive electrode terminal 82a and a negative electrode terminal 83a.

[0024] The case 80 may be made of metal, for example. The case 80 may contain aluminum (Al), for example. The case 80 may have a flat plate-like outer shape. The case 80 may be in the shape of a long plate, for example. The case 80 includes a case main body 81 and a lid.

[0025] The outer shape of the case body 81 may be, for example, a rectangular parallelepiped. The outer shape of the case body 81 may be, for example, a long plate. The width of the case body 81 indicates the outer dimension in the X direction. The width of the case body 81 may be, for example, 500 mm or more, 750 mm or more, or 1000 mm or more. The width of the case body 81 may be, for example, 2000 mm or less, 1500 mm or less, or 1250 mm or less. The height of the case body 81 indicates the outer dimension in the Z direction. The height of the case body 81 may be, for example, 50 mm or more, 75 mm or more, or 100 mm or more. The height of the case body 81 may be, for example, 200 mm or less, 150 mm or less, 125 mm or less, or 100 mm or less. The thickness of the case body 81 indicates the outer dimension in the Y direction. The thickness of the case body 81 may be, for example, 5 mm or more, 10 mm or more, 15 mm or more, or 20 mm or more. The thickness of the case body 81 may be 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, or 10 mm or less. The ratio of width to height may be, for example, 5 to 20. The ratio of width to thickness may be, for example, 50 to 200.

[0026] The case body 81 has an opening. The case body 81 may have, for example, a first opening 81a and a second opening 81b. That is, the case body 81 may be cylindrical. The case body 81 may be rectangular cylindrical, for example. The first opening 81a may be located at one end in the axial direction (X direction). The second opening 81b may be located at the other end in the axial direction.

[0027] The lid closes the opening. There may be one lid or multiple lids. The number of lids corresponds to the number of openings in the case body 81. The case 80 may include, for example, a first lid 82 and a second lid 83. For example, the first lid 82 may close the first opening 81a. For example, the second lid 83 may close the second opening 81b. The lids are provided with electrode terminals. For example, the first lid 82 may be provided with a positive electrode terminal 82a. For example, the second lid 83 may be provided with a negative electrode terminal 83a. One lid may have one electrode terminal. One lid may have multiple electrode terminals. When one lid has multiple electrode terminals, the multiple electrode terminals may have the same polarity or opposite polarities. For example, a liquid injection port 84 may be provided in the lid. For example, the liquid injection port 84 may be provided in the first lid 82.

[0028] For example, the thickness (d1) of the first lid 82 may be smaller than the shortest diameter (D1) of the first opening 81a. The thickness (d1) of the first lid 82 includes the thickness of the positive terminal 82a. The "shortest diameter" refers to the shortest inner diameter of the openings. For example, a relationship such as "d1≦0.9×D1," "d1≦0.8×D1," "d1≦0.7×D1," "d1≦0.6×D1," or "d1≦0.5×D1" may be satisfied. For example, a relationship such as "0.1D1≦d1," "0.2D1≦d1," "0.3D1≦d1," "0.4D1≦d1," or "0.5D1≦d1" may be satisfied.

[0029] For example, the thickness (d2) of the second lid 83 may be smaller than the shortest diameter (D2) of the second opening 81b. The thickness (d2) of the second lid 83 includes the thickness of the negative electrode terminal 83a. For example, the relationship "D1 = D2" may be satisfied. For example, the relationship "d1 = d2" may be satisfied.

[0030] The lid is joined to the case body 81. For example, as shown in Fig. 2, the attitude of the first lid 82 is adjusted so that the first lid 82 fits into the first opening 81a. For example, the first lid 82 may be joined to the case body 81 by irradiating a laser onto the fitting portion between the first lid 82 and the case body 81.

[0031] The power generating element 50 is also referred to as an "electrode body." The power generating element 50 may include, for example, a positive electrode, a negative electrode, a separator, and an electrolyte. The power generating element 50 may be, for example, a laminated or wound type. The positive electrode and the negative electrode may be in a sheet form. The positive electrode may include, for example, lithium iron phosphate, lithium nickel composite oxide, etc. The negative electrode may include, for example, graphite, silicon oxide, silicon, etc.

[0032] The positive electrode terminal 82a penetrates the first lid 82. The positive electrode terminal 82a protrudes from the first lid 82 to the outside of the case 80 along the axial direction (X direction).

[0033] The negative electrode terminal 83a penetrates the second lid 83. In FIG. 2, the negative electrode terminal 83a protrudes in the opposite direction to the positive electrode terminal 82a. In an embodiment, the negative electrode terminal 83a may protrude in the same direction as the positive electrode terminal 82a. That is, both the positive electrode terminal 82a and the negative electrode terminal 83a may be disposed in the second lid 83.

[0034] The electrode terminals may be made of a conductive material. Examples of conductive materials include metal materials, carbon materials, conductive resin materials, and conductive ceramic materials. A conductive ceramic material is preferred as the conductive material. A conductive ceramic material has lower strength than other materials and is therefore more susceptible to breakage when subjected to impact. Therefore, for example, when the energy storage cells 1 are connected to each other, it is possible to cut off the conductive path between an abnormal energy storage cell and a normal cell.

[0035] The conductive ceramic material may be a ceramic material having electrical conductivity. The conductive ceramic material may be a mixture of a ceramic material and a conductive material (such as a carbon material). Examples of the conductive ceramic material include silicon carbide, titanium oxide, titanium nitride, and titanium carbide.

[0036] The electrode terminal may be an integrally molded product, or may be a composite in which a plurality of electrode terminal members that have been molded separately are joined together.

[0037] The power generating element 50 has current collecting tabs. The current collecting tabs may include a positive electrode current collecting tab 51 and a negative electrode current collecting tab 52. The positive electrode current collecting tab 51 and the negative electrode current collecting tab 52 may be an assembly of multiple tabs (for example, a tab bundle).

[0038] The positive electrode current collecting tab 51 outputs the potential of the positive electrode. The positive electrode current collecting tab 51 is electrically connected to the positive electrode included in the power generating element 50, and is also electrically connected to the positive electrode terminal 82a. That is, the positive electrode terminal 82a is electrically connected to the positive electrode of the power generating element 50 via the positive electrode current collecting tab 51. The positive electrode current collecting tab 51 and the positive electrode terminal 82a may be joined (for example, welded).

[0039] The negative electrode current collecting tab 52 outputs the potential of the negative electrode. The negative electrode current collecting tab 52 is electrically connected to the negative electrode included in the power generating element 50, and is also electrically connected to the negative electrode terminal 83a. That is, the negative electrode terminal 83a is electrically connected to the negative electrode of the power generating element 50 via the negative electrode current collecting tab 52. The negative electrode current collecting tab 52 and the negative electrode terminal 83a may be joined (for example, welded).

[0040] The electrodes and current collecting tabs may be integrally formed, or may be formed separately and then joined together.

[0041] The energy storage cell 1 includes a gasket 90. The energy storage cell 1 may include one gasket 90 or multiple gaskets 90 (two gaskets 90a and 90b in FIGS. 3 and 4). The gasket 90 has electrical insulation properties. The gasket 90 may be made of, for example, resin or ceramic. The positive electrode terminal 82a may be inserted through the gasket 90.

[0042] The energy storage cell 1 may further include a sealing material 91. The sealing material 91 provides a seal between the positive electrode terminal 82a and the case 80 (first lid 82). The sealing material 91 may be annular. The sealing material 91 may have electrical insulating properties. The sealing material 91 may be made of, for example, rubber, resin, or the like. The sealing material 91 may have resistance to, for example, the electrolyte solution.

[0043] The energy storage cells 1 can be connected together when used. That is, the energy storage cells 1 can be used as an energy storage module or an energy storage device. Between the energy storage cells 1, a bus bar 92 connects the electrode terminals to each other. The bus bar 92 may connect, for example, the positive electrode terminal 82a and the negative electrode terminal 83a. The bus bar 92 may connect, for example, the positive electrode terminal 82a and the positive electrode terminal 82a. The bus bar 92 may connect, for example, the negative electrode terminal 83a and the negative electrode terminal 83a.

[0044] The bus bar 92 is electrically conductive. The bus bar 92 may be made of, for example, a metal. The bus bar 92 may contain, for example, aluminum (Al), copper (Cu), or the like. The bus bar 92 may be joined to an electrode terminal. For example, the bus bar 92 may be joined to the electrode terminal by resistance welding, ultrasonic welding, laser welding, or the like.

[0045] The electrode terminals have a member contact portion that comes into contact with other members. At least one of the positive electrode terminal 82a and the negative electrode terminal 83a among the electrode terminals has a recess 93 in the member contact portion. By having the recess 93 in the member contact portion of the electrode terminal, the contact area between the electrode terminal and other members is reduced, so that when an external force such as an impact is applied to the electrode terminal, the electrode terminal and other members are more likely to separate. As a result, the electrode terminal and other members separate, and the conductive path can be interrupted.

[0046] Examples of other members include a current collecting tab, a gasket 90, and a bus bar 92. The positive electrode terminal 82a may have a recess 93 at a contact portion with at least one other member. With reference to FIGS. 3 and 4, the positive electrode terminal 82a may have at least one recess 93 (recesses 93a, 93b, and 93c in FIG. 3) or a plurality of recesses 93 (recesses 93a, 93b, and 93c in FIG. 4) at a contact portion with the positive electrode current collecting tab 51, the gasket 90a, and the bus bar 92.

[0047] At least one of the positive electrode terminal 82a and the negative electrode terminal 83a may have a recess 93 in a portion where it contacts another member, and both the positive electrode terminal 82a and the negative electrode terminal 83a may have a recess 93 in a portion where it contacts another member. When both the positive electrode terminal 82a and the negative electrode terminal 83a have a recess 93 in a portion where they contact another member, the positive electrode terminal 82a and the negative electrode terminal 83a may have a recess 93 in a portion where they contact at least one other member. Both the positive electrode terminal 82a and the negative electrode terminal 83a may have at least one recess 93 or multiple recesses 93 in a portion where they contact a current collecting tab, a gasket, or a bus bar.

[0048] At least one of the positive electrode terminal 82a and the negative electrode terminal 83a preferably has a recess 93 at the contact portion with the bus bar. This makes it easier to cut off the electrical continuity between the bus bar and the electrode terminal, and can prevent overcurrent from being transmitted from an abnormal storage cell to a normal cell when an impact is applied to the electrode terminal. It is more preferable that both the positive electrode terminal 82a and the negative electrode terminal 83a have a recess 93 at the contact portion with the bus bar.

[0049] Fig. 5 is a schematic plan view showing an example of a case where the power storage cell of this embodiment is mounted on a vehicle. Fig. 6 is a schematic plan view showing another example of a case where the power storage cell of this embodiment is mounted on a vehicle. The vehicle 100 may be, for example, a BEV (Battery Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle).

[0050] The vehicle 100 is equipped with the energy storage cell 1. In this case, the electrode terminals are configured to face the outside of the vehicle 100. When an impact is applied to the vehicle 100, the electrode terminals having recesses are disposed on the outside of the vehicle 100 where the input force is greater, thereby improving safety against a collision.

[0051] The power storage cell 1 may be mounted on the vehicle 100 as a power storage module. The power storage cell 1 may be mounted on the vehicle 100 as a power storage device. The power storage cell 1 may be mounted in any position. For example, the power storage cell 1 may be disposed under the floor of the vehicle 100. [Explanation of symbols]

[0052] 1 Energy storage cell, 50 Power generation element, 51 Positive electrode current collecting tab, 52 Negative electrode current collecting tab, 80 Case, 81 Case body, 81a First opening, 81b Second opening, 82 First lid, 82a Positive electrode terminal, 83 Second lid, 83a Negative electrode terminal, 84 Inlet, 90, 90a, 90b Gasket, 91 Sealing material, 92 Bus bar, 93, 93a, 93b, 93c Recess, 100 Vehicle.

Claims

1. An electricity storage cell including a case, electrode terminals, and a power generation element, the case accommodates the power generating element, the electrode terminals include a positive terminal and a negative terminal; the electrode terminal has a member contact portion that comes into contact with another member, At least one of the positive electrode terminal and the negative electrode terminal has a recess in the member contact portion.

2. The energy storage cell according to claim 1 , wherein the positive electrode terminal and the negative electrode terminal have recesses in the member contact portions.

3. The energy storage cell according to claim 1 or 2, wherein the other member is a bus bar.

4. The energy storage cell according to claim 1 or 2, wherein the electrode terminals are made of a conductive ceramic material.

5. The energy storage cell according to claim 1 or 2, wherein the electrode terminals are configured to face outward from a vehicle when the energy storage cell is mounted on the vehicle.

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