Energy storage element

Abstract

To provide a power storage element with lateral terminals that makes it easier to ensure dimensional accuracy. [Solution] The energy storage element 1 of this embodiment comprises a case having a case body 31 and a cover portion 32, and a first terminal 42 that conducts electrical conductivity between the inside and outside of the case and is exposed to the outside of the case. The case body includes a peripheral wall component 312 that constitutes the peripheral wall of the case, and a first opening 301 formed by the peripheral wall component. The cover portion closes the first opening. The peripheral wall component includes a second opening 302 formed in a part of the peripheral wall component. The first terminal is positioned at the second opening, and the first opening and the second opening are connected.

Description

Technical Field

[0001] The present invention relates to a power storage element provided with terminals.

Background Art

[0002] Conventionally, a rectangular battery provided with terminals has been known (see Patent Document 1). Patent Document 1 discloses a method for manufacturing a rectangular battery 600 including a battery case 610 that houses an electrode body 630 (see FIGS. 8 and 9). This battery case 610 includes a rectangular bottom surface 611, a pair of long side surfaces 612 that have the long side of the bottom surface 611 as one side and face each other, and a pair of short side surfaces 613 that have the short side of the bottom surface 611 as one side and face each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, due to the demand for lower height, there has been a need for a so-called horizontal terminal type power storage element in which terminals are arranged on the short side surface 613 of the battery case 610.

[0005] In the case of this horizontal terminal type power storage element, a configuration in which the terminals are arranged on the side surface of the battery case 610 (for example, the second member 622 and the third member 623 that constitute the short side surface 613) can be considered.

[0006] In this case, when manufacturing the power storage element 600, it is difficult to ensure dimensional accuracy in the power storage element 600 due to manufacturing errors and the like that occur between the respective components and configurations, such as the degree of bending of the long side surface 612 with respect to the bottom surface 611 in the first member 621 that constitutes the bottom surface 611 and the pair of long side surfaces 612, and the positions of the second member 622 and the third member 623 with respect to the electrode body 630.

[0007] Therefore, the objective of this embodiment is to provide an energy storage element that makes it easy to ensure dimensional accuracy. [Means for solving the problem]

[0008] The energy storage element of this embodiment is A case having a case body and a cover part, The case comprises a first terminal that conducts electrical conductivity between the inside and outside of the case and is exposed to the outside of the case, The case body includes a peripheral wall component included in the peripheral wall of the case, and a first opening formed by the peripheral wall component. The cover portion closes the first opening, The peripheral wall component includes a second opening formed in a part of the peripheral wall component, The first terminal is positioned in the second opening. The first opening and the second opening are connected. [Effects of the Invention]

[0009] Based on the above, this embodiment provides an energy storage element that makes it easier to ensure dimensional accuracy. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic perspective view of the energy storage element according to this embodiment. [Figure 2] Figure 2 is a schematic diagram of the energy storage element as viewed from the Y-axis direction. [Figure 3] Figure 3 is a schematic diagram of the energy storage element as viewed from one side in the X-axis direction. [Figure 4] Figure 4 is a schematic diagram of the energy storage element as viewed from the other side in the X-axis direction. [Figure 5] Figure 5 is a schematic exploded perspective view of the energy storage element. [Figure 6] Figure 6 is a schematic exploded perspective view of a lateral terminal battery, as assumed from a conventional energy storage element. [Figure 7]FIG. 7 is a schematic perspective view of the horizontal terminal battery. [Figure 8] FIG. 8 is a schematic perspective view of a conventional rectangular battery. [Figure 9] FIG. 9 is a schematic exploded perspective view of the unit body included in the rectangular battery.

Embodiments for Carrying Out the Invention

[0011] (1) The power storage element according to one embodiment of the present invention includes a case having a case body and a cover portion, and a first terminal that conducts the inside and outside of the case and is exposed to the outside of the case. The case body includes a peripheral wall component included in the peripheral wall of the case and a first opening formed by the peripheral wall component. The cover portion closes the first opening. The peripheral wall component includes a second opening formed in a part of the peripheral wall component. The first terminal is disposed in the second opening. The first opening and the second opening are connected.

[0012] According to the power storage element according to one embodiment of the present invention, an opening (second opening) for the first terminal is formed in a part of the peripheral wall component, and the first terminal is attached to the terminal opening, so that the dimensional accuracy of the power storage element can be ensured.

[0013] (2) The power storage element according to (1) above includes a second terminal that conducts the inside and outside of the case and is exposed to the outside of the case. The peripheral wall component may include a third opening formed at a position facing the second opening and in which the second terminal is disposed.

[0014] According to the energy storage element described in (2) above, terminals (first terminal, second terminal) are arranged for each opening (second opening, third opening) provided in opposing parts of the peripheral wall component, thereby suppressing manufacturing errors in the position of each terminal relative to the peripheral wall component. This makes it possible to suitably ensure the dimensional accuracy of the energy storage element in the direction in which manufacturing errors tend to be large (the opposing direction between the second opening and the third opening).

[0015] (3) In the energy storage element described in (1) or (2) above, The cover portion is plate-shaped and extends along a planar direction perpendicular to the opening direction of the first opening. The periphery of the cover portion is connected to the periphery of the opening of the first opening, thereby the cover portion closes the first opening. In the case body, the peripheral wall component and the portion that closes the end facing the first opening may be made of a single component.

[0016] According to the energy storage element described in (3) above, the peripheral wall component of the case body and the portion that closes the end of the peripheral wall component facing the first opening are made of a single component, thereby simplifying the case structure.

[0017] (4) The energy storage element described in any one of (1) to (3) above is: The first wall portion is further arranged around the first terminal, The first wall portion may be positioned in the second opening and connected to the peripheral wall component.

[0018] According to the energy storage element described in (4) above, the length of the periphery of the second opening is reduced, thereby reducing the dimensional tolerance around the second opening and ensuring the dimensional accuracy of the energy storage element.

[0019] (5) In the energy storage element described in (4) above, The peripheral wall of the case includes the peripheral wall component and the first wall portion, The outer surface of the peripheral wall is composed of four surfaces, including the first surface. The second opening is formed on the first surface, The area of ​​the second opening may be smaller than the area of ​​the first surface.

[0020] According to the energy storage element described in (5) above, the area of ​​the second opening is smaller than the area of ​​the first surface, which reduces the dimensions of the opening edge of the second opening, thereby ensuring the moldability of the case.

[0021] The following describes one embodiment of the present invention with reference to Figures 1 to 7.

[0022] Energy storage elements include primary batteries, secondary batteries, and capacitors. In this embodiment, a rechargeable secondary battery will be described as an example of an energy storage element. Note that the names of each component (each element) in this embodiment are specific to this embodiment and may differ from the names of each component (each element) in the background art.

[0023] The energy storage element in this embodiment is a non-aqueous electrolyte secondary battery. More specifically, the energy storage element is a lithium-ion secondary battery that utilizes electron transfer that occurs with the movement of lithium ions. This type of energy storage element supplies electrical energy. The energy storage element is used individually or in combination with other elements. Specifically, the energy storage element is used individually when the required output and voltage are small. On the other hand, when at least one of the required output and voltage is large, the energy storage element is used in combination with other energy storage elements in an energy storage device. In the energy storage device, the energy storage elements used in the device supply electrical energy.

[0024] Specifically, as shown in Figures 1 to 5, the energy storage element 1 comprises a case 3 having a case body 31 and a cover portion 32, and a first terminal 42 that conducts electricity between the inside and outside of the case 3 and is exposed to the outside of the case 3. The energy storage element 1 also comprises a second terminal 52 that conducts electricity between the inside and outside of the case 3 and is exposed to the outside of the case 3. In the energy storage element of this embodiment, the first terminal 42 is the positive terminal and the second terminal 52 is the negative terminal. The energy storage element 1 will be described in detail below.

[0025] The energy storage element 1 comprises an electrode body 2 having stacked electrodes (positive electrode, negative electrode) and a case 3 in which the electrode body 2 is housed. The energy storage element 1 also comprises a first terminal section 4 on which a positive electrode terminal 42 is located and a second terminal section 5 on which a negative electrode terminal 52 is located. In the energy storage element 1 of this embodiment, the case 3 includes a part of the first terminal section 4 (a first wall section 41, described later: see Figure 3) and a part of the second terminal section 5 (a second wall section 51, described later: see Figure 4).

[0026] The electrode body 2 is a so-called wound electrode body in which the electrodes are wound in a flattened shape. In this electrode body 2, the electrodes include a positive electrode and a negative electrode, and these positive and negative electrodes are stacked in a state insulated from each other. The energy storage element 1 charges and discharges as lithium ions move between the positive and negative electrodes in the electrode body 2. The energy storage element 1 of this embodiment comprises a plurality of electrode bodies 2 (two in the example shown in Figure 5), and these plurality of electrode bodies 2 are housed in a case 3 such that their winding axes C1 are parallel to each other (see Figure 5).

[0027] The positive electrode comprises a strip-shaped metal foil and a positive electrode active material layer superimposed on the metal foil. This positive electrode active material layer is superimposed on the metal foil with one edge (uncovered portion) in the width direction of the metal foil exposed. The metal foil in this embodiment is, for example, aluminum foil.

[0028] The negative electrode comprises a strip-shaped metal foil and a negative electrode active material layer superimposed on the metal foil. This negative electrode active material layer is superimposed on the metal foil with the other edge (uncoated portion) in the width direction of the metal foil (opposite the uncoated portion of the positive electrode metal foil) exposed. The metal foil in this embodiment is, for example, copper foil.

[0029] In the electrode body 2 of this embodiment, the positive electrode and the negative electrode are wound together in an insulated state by a separator. That is, in the electrode body 2 of this embodiment, the positive electrode, the negative electrode, and the separator are wound together in a stacked state.

[0030] The separator is an insulating component and is placed between the positive and negative electrodes. This insulates the positive and negative electrodes from each other in the electrode body 2. The separator also holds the electrolyte within the case 3. This allows lithium ions to move between the positive and negative electrodes, which are stacked alternately with the separator in between, during the charging and discharging of the energy storage element 1.

[0031] This separator is strip-shaped and composed of a porous membrane such as polyethylene, polypropylene, cellulose, or polyamide. The separator of this embodiment has a substrate formed of a porous membrane and an inorganic layer provided on the substrate. This inorganic layer contains inorganic particles such as SiO2 particles, Al2O3 particles, and boehmite (alumina hydrate). The substrate is formed of polyethylene, for example.

[0032] Case 3 is a rectangular parallelepiped or cubic shape of size corresponding to the electrode body 2 (in this embodiment, two electrode bodies 2), and the electrode body 2 is housed such that the winding axis C1 of the electrode body 2 is aligned with the opposing direction of a pair of opposing wall portions (short wall portions) 314 in the rectangular parallelepiped or cubic shape.

[0033] Case 3 has a case body 31 and a cover portion 32. As described above, Case 3 of this embodiment further has a part of the first terminal portion 4 (first wall portion 41: see Figure 3) and a part of the second terminal portion 5 (second wall portion 51: see Figure 4). That is, Case 3 of this embodiment is composed of a case body 31, a cover portion 32, a first wall portion 41 and a second wall portion 51.

[0034] Case 3 houses the electrolyte solution together with the electrode body 2 within its internal space. For this reason, Case 3 is made of a metal that is resistant to the electrolyte solution. In this embodiment, Case 3 is made of, for example, aluminum or an aluminum-based metal material such as an aluminum alloy.

[0035] Here, the electrolyte is a non-aqueous electrolyte. The electrolyte is obtained by dissolving an electrolyte salt in an organic solvent. Examples of organic solvents include cyclic carbonate esters such as propylene carbonate and ethylene carbonate, and linear carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Examples of electrolyte salts include LiClO4, LiBF4, and LiPF6. The electrolyte in this embodiment is prepared by dissolving 1 mol / L of LiPF6 in a mixed solvent prepared by combining propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a ratio of propylene carbonate:dimethyl carbonate:ethyl methyl carbonate = 3:2:5.

[0036] The case body 31 includes a peripheral wall component 312 that is included in the peripheral wall 30 of the case 3 (see Figure 1) (in other words, it is a part of the peripheral wall 30 of the case 3), and a first opening 301 formed by the peripheral wall component 312 (see Figure 5). Specifically, the case body 31 comprises a plate-shaped closing portion 311 and a cylindrical peripheral wall component 312 connected to the periphery of the closing portion 311. In this case body 31, the peripheral wall component 312 and the portion 311 that closes the end of the peripheral wall component 312 facing the first opening 301 (i.e., the closing portion) are made of a single member. The case body 31 of this embodiment is formed by drawing.

[0037] The closure portion 311 is located at the lower end of the case body 31 when the case body 31 is positioned with the first opening 301 facing upwards (i.e., it becomes the bottom wall of the case body 31 when the first opening 301 is facing upwards). The closure portion 311 is rectangular in shape (more specifically, a rectangle) when viewed from the direction normal to the closure portion 311.

[0038] In the following, the direction of the longer side of the closure portion 311 is defined as the X-axis direction of the Cartesian coordinate system, the direction of the shorter side of the closure portion 311 is defined as the Y-axis direction of the Cartesian coordinate system, and the direction of the normal to the closure portion 311 is defined as the Z-axis direction of the Cartesian coordinate system.

[0039] The peripheral wall component 312 is cylindrical in shape and extends in the Z-axis direction, with a first opening 301 formed at the end closest to the cover component 32. In this embodiment, the peripheral wall component 312 includes a second opening 302 formed in a part of the peripheral wall component 312. This second opening 302 is connected to the first opening 301. The peripheral wall component 312 also includes a third opening 303 formed at a position opposite the second opening 302. This third opening 303 is connected to the first opening 301.

[0040] Specifically, the peripheral wall component 312 is rectangular in shape, or more precisely, flattened rectangular in shape. This peripheral wall component 312 is made up of a single continuous plate material that extends around its entire circumference.

[0041] More specifically, the peripheral wall component 312 has a pair of long wall portions 313 extending from the long side of the periphery of the closing portion 311, and a pair of short wall portions 314 extending from the short side of the periphery of the closing portion 311. In other words, the pair of long wall portions 313 face each other with a gap in the Y-axis direction (more specifically, a gap corresponding to the short side of the periphery of the closing portion 311), and the pair of short wall portions 314 face each other with a gap in the X-axis direction (more specifically, a gap corresponding to the long side of the periphery of the closing portion 311).

[0042] Each of the pair of long wall sections 313 is a rectangular shape that is elongated in the X-axis direction when viewed from the Y-axis direction. The dimension of the long wall section 313 in the X-axis direction is greater than the dimension of the short wall section 314 in the Y-axis direction.

[0043] One of the pair of short wall portions 314 (the leftmost in Figure 2), the first short wall portion 314a, has a second opening 302 in the portion including the end portion (first end portion) 3140a that is close to the cover portion 32 in the Z-axis direction.

[0044] The second opening 302 is rectangular in shape when viewed from the X-axis direction (in the example shown in Figure 3, it is a square or approximately square) and is formed in the center of the first end portion 3140a of the first short wall portion 314a in the Y-axis direction. In other words, the second opening 302 is formed to include the second region from each end when the length of the first short wall portion 314a in the Y-axis direction is divided into three parts. The dimension of this second opening 302 in the Y-axis direction is smaller than the dimension of the first short wall portion 314a in the Y-axis direction. As a result, the second opening 302 is positioned at a predetermined interval α1 (see Figure 3) from each outer end of the first short wall portion 314a in the Y-axis direction. This predetermined interval α1 is preferably 1.5 mm or more in order to ensure the moldability of the case body 31.

[0045] In this embodiment, in the rectangular second opening 302, the three consecutive sides 302a, 302b, and 302c of the rectangular shape are formed by the first short wall portion 314a, and the remaining side 302d is formed by the cover portion 32 when the first opening 301 is closed by the cover portion 32 (see Figure 3). In other words, when the first opening 301 is not closed by the cover portion 32, the end of the second opening 302 on the cover portion 32 side (the region corresponding to side 302d) is open (see Figure 5).

[0046] Furthermore, the other short wall portion (the one on the right in Figure 2) 314b of the pair of short wall portions 314 has a third opening 303 in the portion including the end portion (second end portion) 3140b that is close to the cover portion 32 in the Z-axis direction.

[0047] The third opening 303, like the second opening 302, is rectangular in shape when viewed from the X-axis direction (in the example shown in Figure 4, it is a square or approximately square), and is formed in the center of the second end 3140b of the second short wall portion 314b in the Y-axis direction. In other words, the third opening 303 is formed to include the second region from each end when the Y-axis direction of the second short wall portion 314b is divided into three parts. The Y-axis dimension of this third opening 303 is smaller than the Y-axis dimension of the second short wall portion 314b. As a result, the third opening 303 is positioned at a predetermined interval α2 (see Figure 4) from each outer end of the second short wall portion 314b in the Y-axis direction. This predetermined interval α2 is preferably 1.5 mm or more in order to ensure the moldability of the case body 31. In the case body 31 of this embodiment, the predetermined interval α2 in the second short wall portion 314b and the predetermined interval α1 in the first short wall portion 314a are the same. In other words, the third opening 303 has the same shape as the second opening 302.

[0048] In this embodiment, in the rectangular third opening 303, the three consecutive sides 303a, 303b, and 303c of the rectangular shape are formed by the second short wall portion 314b, and the remaining side 303d is formed by the cover portion 32 when the first opening 301 is closed by the cover portion 32 (see Figure 4). In other words, when the first opening 301 is not closed by the cover portion 32, the end of the third opening 303 closest to the cover portion 32 (the region corresponding to side 303d) is open (see Figure 5).

[0049] Each of the short wall portions 314 configured in this way (first short wall portion 314a, second short wall portion 314b) connects the corresponding ends (more specifically, opposite in the Y-axis direction) of a pair of long wall portions 313, thereby forming a rectangular tubular peripheral wall component 312.

[0050] As described above, the case body 31 has a rectangular tube shape (i.e., a bottomed rectangular tube shape) with the end opposite to the first opening 301 in the Z-axis direction closed. Multiple (two in the example shown in Figure 5) electrode bodies 2 are housed in this case body 31, arranged in the Y-axis direction with each winding axis C1 direction facing the X-axis direction (the direction in which the pair of short wall portions 314 face each other).

[0051] The cover portion 32 is a plate-shaped member that closes the first opening 301 of the case body 31. This cover portion 32 is plate-shaped and extends along a plane direction perpendicular to the opening direction of the first opening 301 (i.e., the Z-axis direction). Specifically, the cover portion 32 is a plate-shaped member having a contour shape corresponding to the opening peripheral edge 301a (see Figure 5) of the first opening 301 of the case body 31 as viewed from the Z-axis direction. That is, the cover portion 32 is a rectangular plate material that is elongated in the X-axis direction when viewed from the Z-axis direction. The periphery of the cover portion 32 is connected to the opening peripheral edge 301a of the first opening 301, thereby closing the first opening 301 with the cover portion 32.

[0052] The first terminal portion 4 includes a first wall portion 41 that closes the second opening 302 of the first short wall portion 314a, a positive electrode terminal 42 positioned on the first wall portion 41, and a positive electrode current collector 43 that makes electrical contact between the electrode body 2 and the positive electrode terminal 42 within the case 3 (see Figures 2 and 5).

[0053] The first wall portion 41 is positioned in the second opening 302 and connected to the peripheral wall component 312. Together with the peripheral wall component 312, the first wall portion 41 constitutes the peripheral wall 30 of the case 3. In other words, the first wall portion 41 is part of the peripheral wall 30 of the case 3.

[0054] Specifically, the first wall portion 41 is a plate-shaped member with a shape corresponding to the second opening 302. In this embodiment, the first wall portion 41 is a plate-shaped member with a rectangular shape when viewed from the X-axis direction. The first wall portion 41 is fitted into the second opening 302 and its peripheral edge is welded to the opening peripheral edge of the second opening 302 in the first short wall portion 314a. In this embodiment, the first wall portion 41 is connected to the first short wall portion 314a so as to be flush with the first short wall portion 314a.

[0055] The positive terminal 42 is a part that is electrically connected to the external terminals of other energy storage elements or external devices, and is insulated from the first wall portion 41. Specifically, the positive terminal 42 has a positive terminal body 421 that extends along the first wall portion 41, and a first penetrating portion 422 that extends from the positive terminal body 421 through the first wall portion 41 into the case 3 (see Figure 2).

[0056] In this embodiment, the positive terminal body 421 is smaller than the first wall portion 41 when viewed from the X-axis direction (viewed from the opening direction of the second opening 302) and is positioned on the first wall portion 41 so as to be located inside the periphery of the first wall portion 41. As a result, when viewed from the X-axis direction, the first wall portion 41 is located around the positive terminal body 421.

[0057] The positive electrode terminal 42 is formed from a conductive material. This positive electrode terminal 42 is formed from a highly weldable metal material, such as aluminum or an aluminum alloy.

[0058] The positive electrode current collector 43 is formed of a conductive material and is connected to the electrode body 2 and the positive electrode terminal 42 to provide electrical conductivity. Specifically, the positive electrode current collector 43 is positioned along the inner surface of the case 3 and is joined to the positive electrode of the electrode body 2 and to the first through portion (the part located inside the case 3) 422 of the positive electrode terminal 42. The positive electrode current collector 43 is formed of, for example, aluminum or an aluminum alloy.

[0059] The second terminal portion 5 includes a second wall portion 51 that closes the third opening 303 of the second short wall portion 314b, a negative electrode terminal 52 positioned on the second wall portion 51, and a negative electrode current collector 53 that makes electrical contact between the electrode body 2 and the negative electrode terminal 52 within the case 3 (see Figure 2).

[0060] The second wall portion 51 is positioned in the third opening 303 and connected to the peripheral wall component 312. Together with the peripheral wall component 312, the second wall portion 51 constitutes the peripheral wall 30 of the case 3. That is, the second wall portion 51 is part of the peripheral wall 30 in the case 3. In the case 3 of this embodiment, the peripheral wall 30 is composed of the second wall portion 51, the first wall portion 41, and the peripheral wall component 312.

[0061] Specifically, the second wall portion 51 is a plate-shaped member with a shape corresponding to the third opening 303. In this embodiment, the second wall portion 51 is a rectangular plate-shaped member when viewed from the X-axis direction. The second wall portion 51 is fitted into the third opening 303 and its peripheral edge is welded to the opening peripheral edge of the third opening 303 in the second short wall portion 314b. In this embodiment, the second wall portion 51 is connected to the second short wall portion 314b so as to be flush with the second short wall portion 314b.

[0062] The negative electrode terminal 52 is a part that is electrically connected to the external terminals of other energy storage elements or external equipment, and is insulated from the second wall portion 51. Specifically, the negative electrode terminal 52 has a negative electrode terminal body 521 that extends along the second wall portion 51, and a second penetrating portion 522 that extends from the negative electrode terminal body 521 through the second wall portion 51 into the case 3 (see Figure 2).

[0063] In this embodiment, the negative electrode terminal body 521 is smaller than the second wall portion 51 when viewed from the X-axis direction (viewed from the opening direction of the third opening 303) and is positioned on the second wall portion 51 so as to be located inside the periphery of the second wall portion 51. As a result, when viewed from the X-axis direction, the second wall portion 51 is located around the negative electrode terminal body 521.

[0064] The negative electrode terminal 52 is formed from a conductive material. This negative electrode terminal 52 is formed from a highly weldable metal material, such as copper or a copper alloy.

[0065] The negative electrode current collector 53 is formed of a conductive material and is connected to the electrode body 2 and the negative electrode terminal 52 to provide electrical conductivity. Specifically, the negative electrode current collector 53 is positioned along the inner surface of the case 3 and is joined to the negative electrode of the electrode body 2 and to the second penetration portion (the part located inside the case 3) of the negative electrode terminal 52. The negative electrode current collector 53 is formed of, for example, copper or a copper alloy.

[0066] In case 3 of this embodiment, the first wall portion 41 of the first terminal portion 4 and the second wall portion 51 of the second terminal portion 5, configured as described above, close the second opening 302 and the third opening 303 of the peripheral wall component 312, thereby forming the peripheral wall 30 of case 3. Here, of the four surfaces constituting the outer surface (outer peripheral surface) of the rectangular tubular peripheral wall 30, the surface corresponding to the first wall portion 41 is designated as the first surface S1, and the surfaces in the circumferential direction are designated as the second surface S2, the third surface S3, and the fourth surface S4 in order. The first surface S1 is composed of the outer surface of the first short wall portion 314a and the outer surface of the first wall portion 41 (see Figures 1 and 3). The second surface S2 is composed of the outer surface of one of the pair of long wall portions 313 (first long wall portion) 313a (see Figures 1 and 2). The third surface S3 is composed of the outer surface of the second short wall portion 314b and the outer surface of the second wall portion 51 (see Figure 4). Furthermore, the fourth surface S4 is formed by the outer surface of the other long wall portion (second long wall portion) 313b of the pair of long wall portions 313 (see Figures 3 and 4).

[0067] Next, the manufacturing method of the energy storage element 1 of this embodiment will be described.

[0068] The case body 31 and the cover part 32 are prepared. In this embodiment, the case body 31 is formed by cutting out (opening windows) portions corresponding to the second opening 302 and the third opening 303 from a bottomed rectangular tubular member formed by drawing.

[0069] Furthermore, an electrode unit U is formed in which a first terminal portion 4 and a second terminal portion 5 are connected to multiple electrode bodies 2 (see Figure 5). In forming this electrode unit U, the connection order of the multiple electrode bodies 2, the first wall portion 41, the positive electrode terminal 42, the positive electrode current collector 43, the second wall portion 51, the negative electrode terminal 52, and the negative electrode current collector 53 is not limited.

[0070] Next, the electrode unit U is inserted into the case body 31. At this time, the electrode unit U is inserted into the case body 31 such that the first wall portion 41 of the first terminal portion 4 fits into the second opening 302 of the first short wall portion 314a, and the second wall portion 51 of the second terminal portion 5 fits into the third opening 303 of the second short wall portion 314b.

[0071] When the electrode unit U is inserted into the case body 31, the periphery of the first wall portion 41 of the first terminal portion 4 and the periphery of the opening of the second opening 302 of the first short wall portion 314a are welded together. Additionally, the periphery of the second wall portion 51 of the second terminal portion 5 and the periphery of the opening of the third opening 303 of the second short wall portion 314b are welded together.

[0072] Once the welding of the first wall portion 41 and the second wall portion 51 to the case body 31 is complete, the cover portion 32 is then connected to the opening periphery portion 301a of the first opening 301 in the case body 31. Specifically, the periphery of the cover portion 32 is welded to the opening periphery portion 301a of the first opening 301 in the case body 31, to the edge of the first wall portion 41 facing the cover portion 32, and to the edge of the second wall portion 51 facing the cover portion 32. As a result, the case 3 is sealed.

[0073] Furthermore, regarding the order of welding, the welding of the first wall portion 41 and the second wall portion 51 to the case body 31 may be performed first, or the welding of the cover portion 32 to the case body 31 may be performed first. Also, the welding of the first wall portion 41 and the second wall portion 51 to the case body 31 and the welding of the cover portion 32 to the case body 31 may be performed simultaneously. In other words, the order of welding is not limited. In addition, although the welding in this embodiment is laser welding, any welding technique may be used as long as the case 3 is sealed.

[0074] In this way, when the cover portion 32 is connected to the peripheral edge 301a of the first opening 301, electrolyte is injected into the case 3 from an injection hole (omitted from the drawing) provided at a predetermined position in the case 3, and the injection hole is sealed by an injection plug or the like. As a result, an energy storage element (a so-called horizontal terminal type energy storage element) 1 is formed, with a positive electrode terminal 42 and a negative electrode terminal 52 arranged on the peripheral wall 30 of the cover portion 32 of the case 3.

[0075] The energy storage element 1 described above comprises a case 3 having a case body 31 and a cover portion 32, and a positive electrode terminal (first terminal) 42 that conducts electrical conductivity between the inside and outside of the case 3 and is exposed to the outside of the case 3. The case body 31 includes a peripheral wall component 312 included in the peripheral wall 30 of the case 3, and a first opening 301 formed by the peripheral wall component 312. The cover portion 32 closes the first opening 301, and the peripheral wall component 312 includes a second opening 302 formed in a part of the peripheral wall component 312. The positive electrode terminal 42 is positioned in the second opening 302, and the first opening 301 and the second opening 302 are connected.

[0076] In this way, an opening (second opening) 302 for the positive electrode terminal 42 is formed in a part of the peripheral wall component 312, and the positive electrode terminal 42 is attached to the opening 302 for the terminal (in this embodiment, it is attached via the first wall portion 41, etc.), thereby ensuring the dimensional accuracy of the energy storage element 1. Specifically, it is as follows.

[0077] In a configuration where the positive and negative terminals of an energy storage element are located on the peripheral wall of the case (i.e., a part of the case other than the cover), the electrode body is inserted into the case through an opening formed by the peripheral wall (corresponding to the first opening 301 in this embodiment) with each terminal connected (i.e., with the electrode body unit formed). For example, configurations like those shown in Figures 6 and 7 are conceivable.

[0078] In this configuration, case 3A includes a main body A which includes a rectangular closing portion 311A ​​and a pair of long wall portions 313A which rise along the Z-axis from opposing sides (edges) of the closing portion 311A; a pair of short wall portions 314A which are arranged on which terminals (positive terminal, negative terminal) T are located and which connect the opposing edges of the pair of long wall portions 313A in the Y-axis direction; and a cover portion 32A which closes the opening formed (enclosed) by the respective edges in the Z-axis direction of the pair of long wall portions 313A and the pair of short wall portions 314A. The energy storage element 1A is formed as follows.

[0079] A pair of short wall portions 314A are assembled to the electrode body 2A together with the terminal T to form an electrode body unit U1. With the electrode body 2A of this electrode body unit U1 positioned between a pair of long wall portions 313A of the main body A, the main body A and each of the short wall portions 314A are welded together. Subsequently, with the cover portion 32A covering the opening, the edges of the long wall portions 313A and short wall portions 314A that form the opening are welded to the periphery of the cover portion 32A, thereby forming the case 3A (see Figure 7).

[0080] Here, the main body A is formed by bending a flat metal member. For this reason, when forming the main body A, the angle θ of the long wall portion 313A with respect to the closure portion 311A ​​(see Figure 6) is likely to be greater than or less than 90° due to manufacturing errors. Also, when the short wall portion 314A is assembled to the electrode body 2A together with the terminal T (i.e., when the electrode body unit U1 is formed), manufacturing errors may occur in each component of the electrode body unit U1 including the short wall portion 314A, or assembly errors may occur when each component is assembled to the electrode body 2A. For this reason, when the short wall portion 314A and the cover portion 32A are connected to the main body A to form the case 3A, the dimensional accuracy relative to the design value is likely to decrease (i.e., the dimensional accuracy of the formed energy storage element 1A decreases), which is a problem that is likely to occur.

[0081] Therefore, in the energy storage element 1 of this embodiment, the case body 31 includes a peripheral wall component 312 (in other words, a peripheral wall component 312 that constitutes a part of the peripheral wall 30 of the case 3) included in the peripheral wall 30 of the case 3 (see Figure 1), and a first opening 301 formed by the peripheral wall component 312, the cover portion 32 closes the first opening 301, the peripheral wall component 312 includes a second opening 302 formed in a part of the peripheral wall component 312, and the positive terminal 42 is positioned at the second opening 302 The device employs a configuration in which the first opening 301 and the second opening 302 are connected. That is, in the case body 31, an opening (second opening) 302 for which the positive electrode terminal 42 is placed is provided in a part of the peripheral wall component 312. As a result, bending is not performed at the boundary between the closed portion 311A ​​and the long wall portion 313A as shown in Figure 6, thus suppressing manufacturing errors in the case body 31 (errors in the angle θ between the closed portion 311 and the long wall portion 313 during manufacturing). Consequently, the dimensional accuracy of the energy storage element 1 can be ensured. The length of the second opening 302 in the Z-axis direction is smaller than the length of the portion of the peripheral wall 30 in the Z-axis direction where the second opening 302 is located.

[0082] Furthermore, in the energy storage element 1 of this embodiment, the peripheral wall component 312 includes a third opening 303 formed in a part of the peripheral wall component 312, the negative terminal (second terminal) 52 is positioned in the third opening 303, and the first opening 301 and the third opening 303 are connected.

[0083] Even with this configuration, an opening (third opening) 303 for the negative electrode terminal 52 is formed in a part of the peripheral wall component 312, and the negative electrode terminal 52 is attached to the opening 303 (in this embodiment, it is attached via the second wall component 51, etc.), thereby ensuring the dimensional accuracy of the energy storage element 1. Note that the length of the third opening 303 in the Z-axis direction is smaller than the length of the portion of the peripheral wall 30 where the third opening 303 is located in the Z-axis direction.

[0084] Furthermore, the energy storage element 1 of this embodiment includes a negative electrode terminal (second terminal) 52 that conducts electrical conductivity between the inside and outside of the case 3 and is exposed to the outside of the case 3. The peripheral wall component 312 includes a third opening 303 formed at a position opposite to the second opening 302 and in which the negative electrode terminal 52 is located.

[0085] In this way, by arranging the terminals (positive terminal 42, negative terminal 52) for each opening (second opening 302, third opening 303) provided in opposing parts of the peripheral wall component 312, manufacturing errors regarding the position of each terminal 42, 52 relative to the peripheral wall component 312 are suppressed, thereby ensuring suitable dimensional accuracy of the energy storage element 1 in the X-axis direction (the direction in which the second opening 302 and the third opening 303 face each other), where manufacturing errors tend to be large.

[0086] In other words, if a manufacturing error occurs in the direction in which each terminal (positive terminal 42, negative terminal 52) attached to the peripheral wall component 312 is separated from each other in the X-axis direction, the dimensional error of the energy storage element 1 will be large because it will be the sum of these two manufacturing errors. However, by fixing the positions of the second opening 302 and the third opening 303 in the peripheral wall component 312 and arranging the positive terminal 42 and the negative terminal 52 in each opening 302 and 303, the dimensional error of each terminal 42 and 52 relative to the peripheral wall component 312 is suppressed, thereby effectively suppressing the overall dimensional error of the energy storage element 1 in the X-axis direction.

[0087] Furthermore, in the energy storage element 1 of this embodiment, the cover portion 32 is plate-shaped and extends along a planar direction perpendicular to the opening direction (Z-axis direction) of the first opening 301. The periphery of the cover portion 32 is connected to the opening periphery portion 301a of the first opening 301, thereby the cover portion 32 closes the first opening 301. In the case body 31, the peripheral wall component 312 and the portion (closing portion) 311 that closes the end facing the first opening 301 are made of a single component.

[0088] In this way, the case 3 is simplified by having the peripheral wall component 312 of the case body 31 and the portion (closing portion) 311 that closes the end of the peripheral wall component 312 facing the first opening 301 made of a single component.

[0089] Furthermore, the energy storage element 1 of this embodiment further comprises a first wall portion 41 arranged around the positive terminal (first terminal) 42, the first wall portion 41 being arranged in the second opening 302 and connected to the peripheral wall component 312.

[0090] With this configuration, the length of the periphery of the second opening 302 is reduced (made smaller), which reduces the dimensional tolerance around the second opening 302, thus ensuring the dimensional accuracy of the energy storage element 1.

[0091] Furthermore, the energy storage element 1 of this embodiment further includes a second wall portion 51 arranged around the negative terminal (second terminal) 52, the second wall portion 51 being arranged in the third opening 303 and connected to the peripheral wall component 312.

[0092] With this configuration, the length of the periphery of the third opening 303 is reduced (made smaller), which reduces the dimensional tolerance around the third opening 303, thus ensuring the dimensional accuracy of the energy storage element 1.

[0093] Furthermore, in the energy storage element 1 of this embodiment, the peripheral wall 30 of the case 3 includes a peripheral wall component 312 and a first wall portion 41, and the outer surface of the peripheral wall 30 is composed of four surfaces S1, S2, S3, and S4, including the first surface S1, and the second opening 302 is formed on the first surface S1, and the area of ​​the second opening 302 is smaller than the area of ​​the first surface S1.

[0094] Thus, by making the area of ​​the second opening 302 smaller than the area of ​​the first surface S1, the dimensions (length) of the opening edge of the second opening 302 are reduced, thereby ensuring the formability of the case 3. Moreover, when the positive electrode terminal 42 is fixed to the position of the second opening 302 in the peripheral wall 30 by welding (in this embodiment, fixed to the position of the second opening 302 via the first wall portion 41), the occurrence of liquid leakage due to welding defects is suppressed. In addition, the amount of heat input due to welding is suppressed, and the influence of heat (heat caused by welding) on ​​the electrode body 2 and the seal portion between the first wall portion 41 and the positive electrode terminal 42 is reduced. In other words, the smaller (shorter) the dimensions of the opening edge of the second opening 302, the better.

[0095] Furthermore, in the energy storage element 1 of this embodiment, the peripheral wall 30 of the case 3 includes a peripheral wall component 312 and a second wall component 51, and the outer surface of the peripheral wall 30 is composed of four surfaces S1, S2, S3, and S4 including the first surface S1, and the third opening 303 is formed on the third surface S3, and the area of ​​the third opening 303 is smaller than the area of ​​the third surface S3.

[0096] Thus, by making the area of ​​the third opening 303 smaller than the area of ​​the third surface S3, the dimensions (length) of the opening edge of the third opening 303 are reduced, thereby ensuring the formability of the case 3. Moreover, when the negative electrode terminal 52 is fixed to the position of the third opening 303 in the peripheral wall 30 by welding (in this embodiment, fixed to the position of the third opening 303 via the second wall portion 51), the occurrence of liquid leakage due to welding defects is suppressed. In addition, the amount of heat input due to welding is suppressed, and the influence of heat (heat caused by welding) on ​​the electrode body 2 and the seal portion between the second wall portion 51 and the negative electrode terminal 52 is reduced. In other words, the smaller (shorter) the dimensions of the opening edge of the third opening 303, the better.

[0097] It should be noted that the energy storage element of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0098] In the energy storage element 1 of the above embodiment, the first terminal 42 is located in a wall portion of the peripheral wall 30 formed by a first short wall portion 314a and a first wall portion 41, and the second terminal 52 is located in a wall portion of the peripheral wall 30 formed by a second short wall portion 314b and a second wall portion 51, but the configuration is not limited to this. The first terminal 42 and the second terminal 52 may be located in a common wall portion (a wall portion formed by a first short wall portion 314a and a first wall portion 41, or a wall portion formed by a second short wall portion 314b and a second wall portion 51).

[0099] Furthermore, in the energy storage element 1 of the above embodiment, the first terminal 42 and the second terminal 52 are arranged in the peripheral wall 30 in the wall portions corresponding to the first short wall portion 314a and the second short wall portion 314b, but the configuration is not limited to this. The first terminal 42 and the second terminal 52 may be arranged in at least one of the first long wall portion 313a and the second long wall portion 313b in the peripheral wall 30. In this case, an opening corresponding to the second opening 302 or the third opening 303 is formed in at least one of the first long wall portion 313a and the second long wall portion 313b.

[0100] Furthermore, although the peripheral wall 30 of case 3 in the above embodiment is rectangular, the configuration is not limited to this. The peripheral wall 30 may also be cylindrical.

[0101] Furthermore, although the energy storage element 1 in the above embodiment includes a plurality of electrode bodies 2, it is not limited to this configuration. The energy storage element 1 may also have a configuration that includes a single electrode body 2.

[0102] Furthermore, in the energy storage element 1 of the above embodiment, the electrode body 2 is a wound type in which a strip-shaped electrode is wound around a winding axis C1, but it is not limited to this configuration. The electrode body 2 may be a laminated type in which single-leaf electrodes are stacked, or it may be a bellows type. [Explanation of Symbols]

[0103] 1, 1A... Energy storage element, 2, 2A... Electrode body, 3, 3A... Case, 30... Peripheral wall of the case, 301... First opening, 301a... Peripheral edge of the opening, 302... Second opening, 302a, 302b, 302c, 302d... Sides corresponding to the periphery of the second opening, 303... Third opening, 303a, 303b, 303c, 303d... Sides corresponding to the periphery of the third opening, 31...Case body, 311, 311A...Closing part, 312...Peripheral wall component, 313, 313A...Long wall part, 313a...First long wall part (long wall part), 313b... Second long wall part (long wall part) part), 314, 314A...short wall part, 314a...first short wall part (short wall part), 3140a...first end part, 314b...second short wall part (short wall part), 3140b...second end part, 32, 3 2A...Cover section, 4...First terminal section, 41...First wall section, 42...Positive terminal (first terminal), 421...Positive terminal body, 422...First through section, 43...Positive current collector, 5...Second terminal section, 51...Second wall section, 52...Negative terminal (second terminal), 521...Negative terminal body, 522...Second through section, 53...Negative current collector, 600...Rectangular battery (energy storage element), 600...Storage Electrical element, 610...Battery case, 611...Bottom surface, 612...Long side surface, 613...Short side surface, 621...First component, 622...Second component, 630...Electrode body, A...Main body, C1...Winding shaft, S1...First surface, S2...Second surface, S3...Third surface, S4...Fourth surface, T...Terminal, U, U1...Electrode body unit, α1, α2...Predetermined interval, θ...Angle of the long wall portion relative to the closed portion

Claims

1. A case having a case body and a cover part, The case comprises a first terminal that conducts electrical conductivity between the inside and outside of the case and is exposed to the outside of the case, The case body includes a peripheral wall component included in the peripheral wall of the case, and a first opening formed by the peripheral wall component. The cover portion closes the first opening, The peripheral wall component includes a second opening formed in a part of the peripheral wall component, The first terminal is positioned in the second opening. A storage element in which the first opening and the second opening are connected.

2. The case is provided with a second terminal that is electrically conductive to the inside and outside of the case and is exposed to the outside of the case, The energy storage element according to claim 1, wherein the peripheral wall component includes a third opening formed at a position opposite to the second opening and on which the second terminal is located.

3. The cover portion is plate-shaped and extends along a planar direction perpendicular to the opening direction of the first opening. The periphery of the cover portion is connected to the periphery of the opening of the first opening, thereby the cover portion closes the first opening. The energy storage element according to claim 1 or 2, wherein the peripheral wall component and the portion that closes the end facing the first opening are made of a single member in the case body.

4. The first wall portion is further arranged around the first terminal, The energy storage element according to claim 1 or 2, wherein the first wall portion is arranged in the second opening and connected to the peripheral wall component.

5. The peripheral wall of the case includes the peripheral wall component and the first wall portion, The outer surface of the peripheral wall is composed of four surfaces, including the first surface. The second opening is formed on the first surface, The energy storage element according to claim 4, wherein the area of ​​the second opening is smaller than the area of ​​the first surface.

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