Electric storage cell and electric storage module

Abstract

To suppress occurrence of a short circuit.SOLUTION: The power storage cell includes a case and a power generation element, the case accommodates the power generation element, the case includes a case body and a lid, the lid is provided with an electrode terminal, the electrode terminal includes a first portion, a second portion, and a third portion, the first portion is located outside the case, the third portion is located inside the case, the second portion connects the first portion and the third portion to each other, and the third portion is connected to the power generation element, the second portion has a smaller diameter than the first portion and the third portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Japanese Patent Application Laid-Open No. 2022-108655 (Patent Document 1) discloses a secondary battery including an electrode terminal that functions as a fuse. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-108655 Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, an electrode terminal is provided on a side surface of the energy storage cell. In this case, if an external force such as an impact is applied to the electrode terminal, the electrode terminal may be damaged, which may cause a short circuit.

[0005] An object of the present disclosure is to suppress the occurrence of short circuits. [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] Includes a case and power generating elements. the case accommodates the power generating element, The case includes a case body and a lid, The lid is provided with an electrode terminal, the electrode terminal includes a first portion, a second portion, and a third portion; the first part is located outside the case; the third portion is located inside the case, the second section connects the first section and the third section; the third part is connected to the power generating element, The second portion has a smaller diameter than the first portion and the third portion.

[0008] The second section has a smaller diameter than the first and third sections. Therefore, when an external force such as an impact is applied to the electrode terminal, the pressure per unit area applied to the second section is greater than that applied to the first and third sections, causing the second section to be selectively damaged. In other words, the second section functions as an external force suppression section, interrupting the conductive path within the energy storage cell. As a result, it is expected that the occurrence of a short circuit will be suppressed.

[0009] [2] The storage cell according to [1], wherein at least a portion of the second portion is located inside the case.

[0010] [3] The energy storage cell according to [1] or [2], wherein the first portion and the second portion are separated when an external force is applied to the electrode terminal.

[0011] [4] A battery comprising a plurality of storage cells according to any one of [1] to [3] and a bus bar, The bus bar connects the first portions between adjacent ones of the energy storage cells.

[0012] 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]

[0013] [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 an electrode terminal in this embodiment. [Figure 4] FIG. 4 is a schematic plan view showing another example of an electrode terminal in this embodiment. [Figure 5] FIG. 5 is a schematic plan view showing an example of the vicinity of an electrode terminal in this embodiment. [Figure 6] FIG. 6 is a schematic plan view showing an example of the vicinity of an electrode terminal when an external force is applied to the electrode terminal in this embodiment. [Figure 7] FIG. 7 is a schematic plan view showing another example of the vicinity of the electrode terminal when an external force is applied to the electrode terminal in this embodiment. [Figure 8] FIG. 8 is a side view showing an example of the electricity storage module according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] <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.

[0015] 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."

[0016] 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.

[0017] 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).

[0018] "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.

[0019] "Electrode" is a general term for positive and negative electrodes. Similarly, for example, "electrode terminal" is a general term for positive and negative terminals.

[0020] <Energy storage cell> Fig. 1 is a schematic diagram showing an example of a storage cell according to this embodiment. Fig. 2 is a schematic cross-sectional view showing an example of a storage cell according to this embodiment. The storage cell 1 includes a case 80 and a power generating element 50. The case 80 houses the power generating element 50. The case 80 includes a case body 80a and a lid.

[0021] (case) The case 80 may be made of, for example, metal. The case 80 may contain, for example, aluminum (Al) or the like. The case 80 may have a flat plate-like outer shape. The case 80 may be, for example, in the shape of a long plate.

[0022] (Case body) The width of the case body 80a indicates the outer dimension in the X direction. The width of the case body 80a may be, for example, 500 mm or more, 750 mm or more, or 1000 mm or more. The width of the case body 80a may be, for example, 2000 mm or less, 1500 mm or less, or 1250 mm or less. The height of the case body 80a indicates the outer dimension in the Z direction. The height of the case body 80a may be, for example, 50 mm or more, 75 mm or more, or 100 mm or more. The height of the case body 80a 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 80a indicates the outer dimension in the Y direction. The thickness of the case body 80a 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 80a 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.

[0023] The case body 80a has an opening. The case body 80a may have, for example, a first opening 81a and a second opening 81b. That is, the case body 80a may be cylindrical. The case body 80a 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.

[0024] (lid) The lid closes the opening. There may be one or more lids. The number of lids corresponds to the number of openings in the case body 80a. The case 80 may include, for example, a first lid 80b and a second lid 80c. For example, the first lid 80b may close the first opening 81a. For example, the second lid 80c may close the second opening 81b. The lids are provided with electrode terminals. For example, a positive electrode terminal 82 may be provided on the first lid 80b. For example, the positive electrode terminal 82 may be electrically isolated from the first lid 80b by an insulating member (not shown). For example, a negative electrode terminal 83 may be provided on the second lid 80c. 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 on the lid. For example, the liquid pouring port 84 may be provided in the first lid 80b, or the liquid pouring port 84 may be provided in the second lid 80c.

[0025] For example, the thickness (d1) of the first lid 80b may be smaller than the shortest diameter (D1) of the first opening 81a. The thickness (d1) of the first lid 80b includes the thickness of the positive terminal 82. 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.

[0026] The lid is joined to the case body 80a. For example, as shown in Fig. 2, the position of the first lid 80b is adjusted so that the first lid 80b fits into the first opening 81a. For example, the first lid 80b may be joined to the case body 80a by irradiating a laser onto the fitting portion between the first lid 80b and the case body 80a.

[0027] (power generation element) 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.

[0028] (electrode terminal) The positive electrode terminal 82 penetrates the first lid 80b. The positive electrode terminal 82 is electrically connected to the positive electrode (power generating element 50) inside the case 80. The positive electrode terminal 82 protrudes from the first lid 80b to the outside of the case 80 along the axial direction (X direction).

[0029] The positive electrode terminal 82 may be made of a conductive material (more specifically, a metal). The positive electrode terminal 82 may be made of, for example, Al or an Al alloy.

[0030] The negative electrode terminal 83 penetrates the second lid 80c. Inside the case 80, the negative electrode terminal 83 is electrically connected to the negative electrode (power generating element 50). In FIG. 2, the negative electrode terminal 83 protrudes in the opposite direction to the positive electrode terminal 82. In an embodiment, the negative electrode terminal 83 may protrude in the same direction as the positive electrode terminal 82. That is, both the positive electrode terminal 82 and the negative electrode terminal 83 may be disposed in the second lid 80c.

[0031] The negative electrode terminal 83 may be made of a conductive material (more specifically, a metal). The negative electrode terminal 83 may be made of, for example, copper (Cu) or a Cu alloy.

[0032] 1(a) and 1(b), the position of the negative electrode terminal 83 in the Z direction is the same as the position of the positive electrode terminal 82. The position of the negative electrode terminal 83 in the Z direction may be different from the position of the positive electrode terminal 82.

[0033] Fig. 3 is a schematic plan view showing an example of an electrode terminal in this embodiment. Fig. 4 is a schematic plan view showing another example of an electrode terminal in this embodiment. Fig. 5 is a schematic plan view showing an example of the vicinity of an electrode terminal in this embodiment. In Figs. 3 to 5, a positive electrode terminal 82 is shown. Although not shown, a negative electrode terminal 83 may also have a similar structure to the positive electrode terminal 82.

[0034] The positive electrode terminal 82 includes a first portion 82a, a second portion 82b, and a third portion 82c. The third portion 82c is located inside the case 80. The third portion 82c is connected to the power-generating element 50. The first portion 82a is located outside the case 80. The first portion 82a includes an end surface of the positive electrode terminal 82. The end surface of the positive electrode terminal 82 may be flat or curved.

[0035] The second portion 82b is located between the first portion 82a and the third portion 82c and connects the first portion 82a and the third portion 82c.

[0036] The first portion 82a and the second portion 82b, and the second portion 82b and the third portion 82c may be joined together. The joining method is not particularly limited, and may be, for example, resistance welding, ultrasonic welding, laser welding, etc. The first portion 82a and the second portion 82b, and the second portion 82b and the third portion 82c may be configured to be constricted.

[0037] The second portion 82b has a smaller diameter than the first portion 82a and the third portion 82c. Therefore, when an external force such as an impact is applied to the positive electrode terminal 82, the pressure per unit area applied to the second portion 82b is greater than that applied to the first portion 82a and the third portion 82c, and the second portion 82b is selectively damaged. In other words, the second portion 82b functions as an external force suppression portion, thereby interrupting the conductive path within the energy storage cell 1. As a result, it is expected that the occurrence of a short circuit will be suppressed.

[0038] The second portion 82b may have a constant diameter. The diameter of the second portion 82b may vary in the axial direction of the positive electrode terminal 82. For example, the second portion 82b may be tapered or inversely tapered in the direction from the third portion 82c toward the first portion 82a.

[0039] The first portion 82a and the third portion 82c may have the same diameter. The first portion 82a may have a larger diameter or a smaller diameter than the third portion 82c.

[0040] The ratio of the diameter of the second portion 82b to the diameter of the first portion 82a may be, for example, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less. The ratio of the diameter of the second portion 82b to the diameter of the first portion 82a may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more. If the outlines of the first portion 82a and the second portion 82b are not circular in a cross section perpendicular to the axial direction of the electrode terminal, the diameters of each portion shall indicate the maximum diameters.

[0041] The ratio of the diameter of the second portion 82b to the diameter of the third portion 82c may be, for example, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less. The ratio of the diameter of the second portion 82b to the diameter of the third portion 82c may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more. If the contours of the third portion 82c and the second portion 82b are not circular in a cross section perpendicular to the axial direction of the electrode terminal, the diameters of each portion shall indicate the maximum diameters.

[0042] At least a portion of second portion 82b may be located inside case 80. This is expected to further suppress the occurrence of short circuits. Also, second portion 82b is preferably located inside case 80. This is expected to further suppress contact between second portion 82b and other components, and to further suppress the occurrence of short circuits.

[0043] The positive electrode terminal 82 may include a plurality of second portions 82b. The plurality of second portions 82b may have the same diameter or may have different diameters.

[0044] Fig. 6 is a schematic plan view showing an example of the vicinity of an electrode terminal when an external force is applied to the electrode terminal in this embodiment. Fig. 7 is a schematic plan view showing another example of the vicinity of an electrode terminal when an external force is applied to the electrode terminal in this embodiment. Positive electrode terminal 82 is shown in Figs. 6 and 7. Although not shown, the same thing can happen to negative electrode terminal 83 as to positive electrode terminal 82.

[0045] As described above, the second portion 82b has a smaller diameter than the first portion 82a and the third portion 82c. Therefore, when an external force such as an impact acts on the positive electrode terminal 82 (first portion 82a) (arrow in FIG. 6(a)), the first portion 82a rotates by the principle of leverage, with the portion where the external force acts as the force point (e.g., A in FIG. 6), the end point of the first portion 82a as the fulcrum (e.g., B in FIG. 6), and the contact portion between the first portion 82a and the second portion 82b as the point of action (e.g., C in FIG. 6). This disconnects the first portion 82a from the two second portions 82b (FIG. 6(b)), thereby interrupting the electrical conduction path within the energy storage cell 1. This is expected to result in suppression of short-circuiting.

[0046] 7, the positive electrode terminal 82 includes two second portions 82b. As described above, when an external force such as an impact is applied to the positive electrode terminal 82 (arrow in FIG. 7(a)), the first portion 82a rotates by the principle of leverage, with the portion where the external force is applied serving as the force point (e.g., D in FIG. 7), the end point of the first portion 82a serving as the fulcrum (e.g., E in FIG. 7), and the contact portion between the first portion 82a and the second portion 82b serving as the action point (e.g., F1 and F2 in FIG. 7), and the first portion 82a is disconnected from the two second portions 82b (FIG. 7(b)), thereby interrupting the conductive path within the energy storage cell 1. As a result, it is expected that the occurrence of a short circuit will be suppressed.

[0047] <Energy storage module> 8 is a side view showing an example of a power storage module according to this embodiment. The power storage module 100 includes a plurality of power storage cells 1 and a bus bar 101. The plurality of power storage cells 1 may be electrically connected in series or in parallel. The number of power storage cells 1 may be, for example, 2 or more, 4 or more, 10 or more, 20 or more, 50 or more, or 100 or more. The number of power storage cells 1 may be, for example, 100 or less, 50 or less, 20 or less, 10 or less, or 4 or less.

[0048] The multiple storage cells 1 are stacked in the Y direction. Adjacent storage cells 1 are inverted in the X direction, so that the positive electrode terminal 82 of one storage cell 1 is adjacent to the negative electrode terminal 83 of the other storage cell 1.

[0049] (busbar) The bus bar 101 is conductive. The bus bar 101 may be made of, for example, a metal. The bus bar 101 may contain, for example, Al, Cu, or the like. The bus bar 101 connects the electrode terminals (first portions) of adjacent energy storage cells 1 to each other. The bus bar 101 may connect, for example, the positive electrode terminal 82 and the negative electrode terminal 83. The bus bar 101 may connect, for example, the positive electrode terminal 82 and the positive electrode terminal 82. The bus bar 101 may connect, for example, the negative electrode terminal 83 and the negative electrode terminal 83. The bus bar 101 may be joined to the electrode terminals (first portions). For example, the bus bar 101 may be joined to the electrode terminals (first portions) by resistance welding, ultrasonic welding, laser welding, or the like.

[0050] 8, the bus bar 101 may be inclined in the Z direction, for example, or may extend parallel to the Y direction, for example.

[0051] Bus bar 101 may be, for example, plate-shaped. Bus bar 101 may have two through holes. Electrode terminals may be inserted through the through holes.

[0052] (others) The energy storage module 100 may further include an annular member (spacer) (not shown). The annular member has electrical insulation properties. The annular member may be made of, for example, resin or ceramic. The electrode terminal may be inserted through the annular member.

[0053] The energy storage module 100 may further include a sealing material (not shown). The sealing material may provide a seal between the electrode terminals and the case 80. The sealing material may be annular. The sealing material may have electrical insulating properties. The sealing material may be made of, for example, rubber or resin. The sealing material may have resistance to, for example, the electrolyte solution. [Explanation of symbols]

[0054] 1 Energy storage cell, 50 Power generation element, 80 Case, 80a Case body, 80b First lid, 80c Second lid, 81a First opening, 81b Second opening, 82 Positive electrode terminal, 82a First part, 82b Second part, 82c Third part, 83 Negative electrode terminal, 84 Inlet, 100 Energy storage module, 101 Bus bar.

Claims

1. a case and a power generating element; the case accommodates the power generating element, The case includes a case body and a lid, The lid is provided with an electrode terminal, the electrode terminal includes a first portion, a second portion, and a third portion; the first portion is located outside the case, the third portion is located inside the case, the second section connects the first section and the third section, the third portion is connected to the power generating element, The second portion has a smaller diameter than the first portion and the third portion.

2. The energy storage cell according to claim 1 , wherein at least a portion of the second portion is located inside the case.

3. The energy storage cell according to claim 1 , wherein the first portion and the second portion are separated when an external force is applied to the electrode terminal.

4. A battery pack including a plurality of the storage cells according to any one of claims 1 to 3 and a bus bar, the bus bar connects the first portions between adjacent ones of the energy storage cells.

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