Electricity storage unit

Abstract

A power storage unit includes a case that houses a power generation element, electrode terminals including a positive electrode terminal and a negative electrode terminal, the electrode terminals having a member contact portion that comes into contact with another member, and a power generation element disposed in the case. At least one of the positive electrode terminal and the negative electrode terminal has a recessed portion in the member contact portion.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a power storage unit. BACKGROUND

[0002] Japanese Patent Application Publication No. 2017-16734 discloses a power storage device provided with a current cutoff mechanism as a safety mechanism in order to prevent an abnormality in the power storage device from being transmitted to other power storage devices. SUMMARY

[0003] However, the current cutoff mechanism described in Japanese Patent Application Publication No. 2017-16734 has a complicated configuration, and a simpler safety mechanism is required.

[0004] An object of the present disclosure is to provide a simpler safety mechanism.

[0005] Hereinafter, the technical configuration and the effects of the present disclosure will be described. However, the mechanism of action includes presumption. The mechanism of action does not limit the technical scope of the present disclosure.

[0006] [1] A power storage unit comprising:

[0007] a case, an electrode terminal, and a power generating element,

[0008] the case housing the power generating element,

[0009] the electrode terminal including a positive electrode terminal and a negative electrode terminal,

[0010] the electrode terminal having a component contact portion that contacts another component,

[0011] at least one of the positive electrode terminal and the negative electrode terminal has a recess at the component contact portion.

[0012] At least one of the positive electrode terminal and the negative electrode terminal has a recess at the component contact portion that contacts another component. By the electrode terminal having a recess at the component contact portion, the contact area of the electrode terminal with the other component is reduced, and thus the electrode terminal and the other component are easily separated in the case where an external force such as an impact is applied to the electrode terminal. As a result, the electrode terminal and the other component are peeled apart, and the conductive path can be cut off.

[0013] [2] The power storage unit according to [1], wherein

[0014] the positive electrode terminal and the negative electrode terminal have recesses at the component contact portion.

[0015] [3] The power storage unit according to [1] or [2], wherein

[0016] the other component is a bus bar.

[0017] [4] The power storage unit according to any one of [1] to [3], wherein

[0018] The electrode terminal is composed of an electrically conductive ceramic material.

[0019] [5] The power storage unit according to any one of [1] to [4], wherein

[0020] In a case where the power storage unit is mounted on a vehicle, the electrode terminal is configured to face an outside of the vehicle.

[0021] Hereinafter, one embodiment of the present disclosure (hereinafter, which can be referred to simply as "the present embodiment") will be described. However, the present embodiment does not limit the technical scope of the present disclosure. The present embodiment is illustrative in all respects. The present embodiment is non-limiting. The technical scope of the present disclosure includes all modifications equivalent to that recited in the scope of claims and within the scope of the present disclosure. For example, any structures extracted from the present embodiment are intended to be combined arbitrarily from the beginning. BRIEF DESCRIPTION OF DRAWINGS

[0022] Features, advantages, and technical and industrial significance of exemplary embodiments of the application will be described below with reference to the accompanying drawings, in which like elements denote like elements, and wherein:

[0023] Figure 1 is a schematic diagram showing an example of a power storage unit in the present embodiment.

[0024] Figure 2 is a schematic cross-sectional view showing an example of a power storage unit in the present embodiment.

[0025] Figure 3 is a schematic plan view showing an example of the vicinity of an electrode terminal in the present embodiment.

[0026] Figure 4 is a schematic plan view showing another example of the vicinity of an electrode terminal in the present embodiment.

[0027] Figure 5 is a schematic plan view showing an example of a case where a power storage unit in the present embodiment is mounted on a vehicle.

[0028] Figure 6 is a schematic plan view showing another example of a case where a power storage unit in the present embodiment is mounted on a vehicle. DETAILED DESCRIPTION

[0029] TERMS AND EXPRESSIONS

[0030] "Have", "include", "possess" and variations thereof are open-ended terms. Open-ended terms can include additional elements, not only the listed elements, and can also exclude additional elements. "Consisting of" is a closed term. However, even if a structure is expressed in a closed term, it can include impurities that are usually attached or additional elements that are not related to the object technology. "Consisting essentially of" is a semi-closed term. In a semi-closed term, elements that do not substantially affect the basic and new characteristics of the object technology are allowed to be added.

[0031] The expressions "may also", "can" and the like are not used in the sense of obligation "must be performed" but in the sense of permission "have the possibility of being performed".

[0032] The geometric terms should not be understood in a strict sense. As geometric terms, for example, "parallel", "perpendicular", "orthogonal" and the like can be exemplified. For example, within a range in which substantially the same or similar functions can be obtained, directions, angles, distances and the like can also be displaced relatively. The geometric terms can include, for example, design, work, manufacturing and the like tolerances, errors and the like. The dimensional relationships in the respective drawings are sometimes inconsistent with the actual dimensional relationships. In order to help the reader understand, the dimensional relationships in the respective drawings are sometimes changed. For example, the length, width, thickness and the like are sometimes changed. A part of the structure is also sometimes omitted.

[0033] Unless otherwise specified, the elements described in the singular form can also include the plural form. For example, the electrode terminal also sometimes represents a plurality of electrode terminals (a group of electrode terminals).

[0034] The "storage unit" represents a battery that can be charged. The storage unit can be, for example, a lithium ion battery. The storage unit can include, for example, a liquid electrolyte (electrolyte solution), a gel electrolyte or a solid electrolyte.

[0035] The "electrode" is a general term of the positive electrode and the negative electrode. Similarly, for example, the "electrode terminal" is a general term of the positive electrode terminal and the negative electrode terminal. The "current collector tab" is a general term of the positive electrode current collector tab and the negative electrode current collector tab.

[0036] The "storage module" includes a plurality of storage units. The storage module is a collection body to which a plurality of storage units are connected. The "storage device" includes a plurality of storage modules. The storage device is a collection body to which a plurality of storage modules are connected.

[0037] Storage unit

[0038] Figure 1 is a schematic diagram representing an example of the storage unit in the present embodiment. Figure 2 is a schematic cross-sectional view representing an example of the storage unit in the present embodiment. Figure 3This is a schematic top view showing an example of the vicinity of the electrode terminals in this embodiment. Figure 4 This is a schematic top view showing another example of the vicinity of the electrode terminals in this embodiment. Figure 3 And in 4, the vicinity of the positive terminal 82a is shown. Although not shown, the vicinity of the negative terminal 83a may also have the same structure as the positive terminal 82a.

[0039] The energy storage unit 1 includes a housing 80, electrode terminals, and a power generation element 50. The housing 80 houses the power generation element 50. The electrode terminals include a positive terminal 82a and a negative terminal 83a.

[0040] The housing 80 may also be made of metal, for example. The housing 80 may contain aluminum (Al) or the like. The housing 80 may also have a flat, plate-like shape, for example, a long, narrow plate. The housing 80 includes a housing body 81 and a cover.

[0041] The outer shape of the housing body 81 can be, for example, a cuboid shape. The outer shape of the housing body 81 can also be, for example, a long strip plate shape. The width of the housing body 81 represents the outer dimension in the X direction. The width of the housing body 81 can be, for example, 500 mm or more, 750 mm or more, or 1000 mm or more. The width of the housing body 81 can be, for example, less than 2000 mm, less than 1500 mm, or less than 1250 mm. The height of the housing body 81 represents the outer dimension in the Z direction. The height of the housing body 81 can be, for example, 50 mm or more, 75 mm or more, or 100 mm or more. The height of the housing body 81 can be, for example, less than 200 mm, less than 150 mm, less than 125 mm, or less than 100 mm. The thickness of the housing body 81 represents the outer dimension in the Y direction. The thickness of the housing body 81 can be, for example, more than 5 mm, more than 10 mm, more than 15 mm, or more than 20 mm. The thickness of the housing body 81 can be less than 30 mm, less than 25 mm, less than 20 mm, less than 15 mm, or less than 10 mm. The width-to-height ratio can be, for example, 5 to 20. The width-to-thickness ratio can be, for example, 50 to 200.

[0042] The housing body 81 has an opening. The housing body 81 may also have a first opening 81a and a second opening 81b, for example. That is, the housing body 81 may also be cylindrical. The housing body 81 may also be rectangular. The first opening 81a may also be located at one end in the axial direction (X direction). The second opening 81b may also be located at the other end in the axial direction.

[0043] The cap blocks the opening. There can be one or more caps. The number of caps corresponds to the number of openings in the housing body 81. The housing 80 may also include, for example, a first cap 82 and a second cap 83. For example, the first cap 82 may also block the first opening 81a. For example, the second cap 83 may also block the second opening 81b. Electrode terminals are provided on the caps. For example, a positive terminal 82a may be provided on the first cap 82. For example, a negative terminal 83a may be provided on the second cap 83. A cap may have one electrode terminal. A cap may have multiple electrode terminals. In the case where a cap has multiple electrode terminals, the multiple electrode terminals may have the same polarity or different polarities. For example, a liquid injection port 84 may also be provided on the cap. For example, a liquid injection port 84 may also be provided on the first cap 82.

[0044] For example, the thickness (d1) of the first cover 82 can also be smaller than the shortest diameter (D1) of the first opening 81a. The thickness (d1) of the first cover 82 includes the thickness of the positive terminal 82a. "Shortest diameter" refers to the shortest inner diameter among the inner diameters of the opening. For example, relationships such as "d1≤0.9×D1", "d1≤0.8×D1", "d1≤0.7×D1", "d1≤0.6×D1", or "d1≤0.5×D1" can also be satisfied. For example, relationships such as "0.1D1≤d1", "0.2D1≤d1", "0.3D1≤d1", "0.4D1≤d1", or "0.5D1≤d1" can also be satisfied.

[0045] For example, the thickness (d2) of the second cover 83 can also be smaller than the shortest diameter (D2) of the second opening 81b. The thickness (d2) of the second cover 83 includes the thickness of the negative terminal 83a. For example, the relationship "D1 = D2" can also be satisfied. For example, the relationship "d1 = d2" can also be satisfied.

[0046] The cover engages with the housing body 81. For example, as... Figure 2 As shown, the posture of the first cover 82 is adjusted so that the first cover 82 fits into the first opening 81a. For example, the first cover 82 can also be joined to the housing body 81 by irradiating the fitting portion of the first cover 82 and the housing body 81 with a laser.

[0047] The power generation element 50 is also referred to as an "electrode". The power generation element 50 may include, for example, a positive electrode, a negative electrode, a separator, and an electrolyte. The power generation element 50 may be of a laminated or wound type. The positive and negative electrodes may be in 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.

[0048] The positive terminal 82a penetrates the first cover 82. The positive terminal 82a protrudes from the first cover 82 toward the outside of the housing 80 along the axial direction (X direction).

[0049] The negative extreme particle 83a penetrates the second cover 83. In Figure 2 In this configuration, the negative terminal 83a protrudes in the opposite direction to the positive terminal 82a. In one embodiment, the negative terminal 83a may also protrude in the same direction as the positive terminal 82a. That is, both the positive terminal 82a and the negative terminal 83a may be disposed on the second cover 83.

[0050] The electrode terminals can also be made of conductive materials. Examples of conductive materials include metallic materials, carbon materials, conductive resin materials, and conductive ceramic materials. Conductive ceramic materials are preferred as conductive materials. Conductive ceramic materials are weaker than other materials and are therefore easily damaged under impact. Therefore, for example, when the energy storage cells 1 are connected to each other, the conductive path between the abnormal energy storage cell and the normal cell can be cut off.

[0051] Conductive ceramic materials can also be ceramic materials that are conductive. Conductive ceramic materials can be mixtures of ceramic materials and conductive materials (such as carbon materials). Examples of conductive ceramic materials include silicon carbide, titanium oxide, titanium nitride, and titanium carbide.

[0052] In addition, the electrode terminals can be integrally molded or composites formed by joining multiple separately molded electrode terminal components.

[0053] The power generation element 50 has current collectors. The current collectors may include a positive current collector 51 and a negative current collector 52. The positive current collector 51 and the negative current collector 52 may also be an assembly of multiple current collectors (e.g., a bundle of current collectors).

[0054] The positive current collector 51 outputs a positive potential. The positive current collector 51 is electrically connected to the positive terminal of the power generation element 50 and also to the positive terminal 82a. That is, the positive terminal 82a is electrically connected to the positive terminal of the power generation element 50 via the positive current collector 51. The positive current collector 51 and the positive terminal 82a can also be joined (e.g., soldered).

[0055] The negative current collector 52 outputs the potential of the negative terminal. The negative current collector 52 is electrically connected to the negative terminal included in the power generation element 50, and is also electrically connected to the negative terminal 83a. That is, the negative terminal 83a is electrically connected to the negative terminal of the power generation element 50 via the negative current collector 52. The negative current collector 52 and the negative terminal 83a can also be joined (e.g., soldered).

[0056] In addition, each electrode and each current collector can be formed integrally or separately and joined together.

[0057] The energy storage unit 1 includes a gasket 90. The energy storage unit 1 may include one gasket 90 or multiple gaskets 90 (in...).Figure 3 and Figure 4 In this configuration, there are two gaskets 90a and 90b. Gasket 90 is electrically insulating. Gasket 90 can also be made of resin, ceramic, etc. The positive terminal 82a can also be inserted into gasket 90.

[0058] The energy storage unit 1 may also include a sealing material 91. The sealing material 91 seals the positive terminal 82a with the housing 80 (first cover 82). The sealing material 91 may also be annular. The sealing material 91 may also be electrically insulating. The sealing material 91 may be made of, for example, rubber, resin, etc. The sealing material 91 may also be resistant to electrolyte.

[0059] The energy storage unit 1 can be connected and used. That is, the energy storage unit 1 can be used as an energy storage module or energy storage device. A busbar 92 connects the electrode terminals of the energy storage units 1 to each other. The busbar 92 can also connect the positive terminal 82a to the negative terminal 83a, for example. The busbar 92 can also connect the positive terminal 82a to the positive terminal 82a, for example. The busbar 92 can also connect the negative terminal 83a to the negative terminal 83a, for example.

[0060] Busbar 92 is conductive. Busbar 92 may also be made of metal, for example, aluminum (Al), copper (Cu), etc. Busbar 92 may also be joined to electrode terminals. For example, busbar 92 may be joined to electrode terminals by resistance welding, ultrasonic welding, laser welding, etc.

[0061] The electrode terminal has a component contact portion that contacts other components. At least one of the positive terminal 82a and the negative terminal 83a of the electrode terminal has a recess 93 in the component contact portion. By having a recess 93 in the component contact portion of the electrode terminal, the contact area between the electrode terminal and other components is reduced, so the electrode terminal can easily separate from other components when subjected to external forces such as impacts. As a result, the electrode terminal is peeled off from other components, and the conductive path can be cut off.

[0062] Other components may include, for example, current collectors, gaskets 90, busbars 92, etc. The positive terminal 82a may also have a recess 93 in its contact portion with at least one other component. See also... Figure 3 and Figure 4 The positive terminal 82a may have at least one recess 93 at its contact portion with the positive current collector 51, the gasket 90a, and the busbar 92. Figure 3 The middle part consists of recesses 93a, 93b, and 93c, and it can also have multiple recesses 93 (in Figure 4 The middle part consists of multiple recesses 93a, 93b, and 93c.

[0063] It is permissible for at least one of the positive terminal 82a and the negative terminal 83a to have a recess 93 at its component contact portion with other components; alternatively, both the positive terminal 82a and the negative terminal 83a may have a recess 93 at their component contact portions with other components. If both the positive terminal 82a and the negative terminal 83a have a recess 93 at their component contact portions with other components, both the positive terminal 82a and the negative terminal 83a may also have a recess 93 at their component contact portions with at least one other component. Both the positive terminal 82a and the negative terminal 83a may have at least one recess 93, or multiple recesses 93, at their contact portions with the current collector, gasket, and busbar.

[0064] Preferably, at least one of the positive terminal 82a and the negative terminal 83a has a recess 93 at its contact portion with the busbar. This facilitates the disconnection of the busbar from the electrode terminals and, in the event of an impact on the electrode terminals, suppresses the transfer of overcurrent from the malfunctioning storage cell to the normal cell. More preferably, both the positive terminal 82a and the negative terminal 83a have a recess 93 at their contact portions with the busbar.

[0065] Figure 5 This is a schematic top view showing an example of a vehicle in which the energy storage unit of this embodiment is mounted. Figure 6 This is a schematic top view illustrating another example of mounting the energy storage unit of this embodiment in a vehicle. The vehicle 100 may be, for example, a BEV (Battery Electric Vehicle), a HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle).

[0066] The vehicle 100 is equipped with an energy storage unit 1. In this case, the electrode terminals are configured to face outwards from the vehicle 100. In the event of an impact to the vehicle 100, by arranging the electrode terminals with recesses on the outer side of the vehicle 100 where the force input is large, safety against collisions can be improved.

[0067] Furthermore, the energy storage unit 1 can also be mounted in the vehicle 100 as an energy storage module. The energy storage unit 1 can also be mounted in the vehicle 100 as an energy storage device. The mounting location of the energy storage unit 1 is arbitrary. For example, the energy storage unit 1 can also be configured under the floor of the vehicle 100.

Claims

1. A power storage unit comprising: a case, an electrode terminal, and a power generating element, the case housing the power generating element, the electrode terminal including a positive electrode terminal and a negative electrode terminal, the electrode terminal having a component contact portion that contacts another component, at least one of the positive electrode terminal and the negative electrode terminal having a recess in the component contact portion.

2. The power storage unit according to claim 1, wherein the positive electrode terminal and the negative electrode terminal each have a recess in the component contact portion.

3. The power storage unit according to claim 1 or 2, wherein the other component is a bus bar.

4. The power storage unit according to claim 1 or 2, wherein the electrode terminal is composed of an electrically conductive ceramic material.

5. The power storage unit according to claim 1 or 2, wherein in a case where the power storage unit is mounted on a vehicle, the electrode terminal is configured to face an outside of the vehicle.

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