Power storage cell

Abstract

To improve powering of liquid.SOLUTION: A power storage cell includes a case, an electrode body, and electrolyte. The case houses the electrode body and the electrolyte. The case has a first bottom wall, a peripheral wall, and a second bottom wall. The second bottom wall faces the first bottom wall. The peripheral wall connects the first bottom wall to the second bottom wall. The peripheral wall includes a pair of main walls and a pair of side walls. The pair of main walls face each other. The pair of side walls face each other. The pair of side walls interconnect the pair of main walls. Each of the pair of main walls has a larger area than each of the side walls. Within the case, at least one of the pair of side walls has a groove formed in the surface. The groove extends toward the second bottom wall from the first bottom wall.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Japanese Patent Application Laid-Open No. 2009-301892 discloses a porous material that surrounds the periphery of an electrode body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-301892 A Summary of the Invention [Problem to be solved by the invention]

[0004] It has been proposed to place a porous material around the electrode body inside the case. The electrolyte may permeate the porous material. The placement of the porous material is expected to improve the injection efficiency. However, the porous material reduces the storage space of the electrode body, which may reduce the energy density of the storage cell.

[0005] An object of the present disclosure is to improve injectability. [Means for solving the problem]

[0006] 1. An energy storage cell according to an aspect of the present disclosure includes, for example, the following configuration. The energy storage cell includes a case, an electrode assembly, and an electrolyte. The case houses the electrode assembly and the electrolyte. The case has a first bottom wall, a peripheral wall, and a second bottom wall. The second bottom wall faces the first bottom wall. The peripheral wall connects the first bottom wall and the second bottom wall. The peripheral wall includes a pair of main walls and a pair of side walls. The pair of main walls face each other. The pair of side walls face each other. The pair of side walls connect the pair of main walls. Each of the pair of main walls has an area larger than each of the pair of side walls. Within the case, a groove is formed on a surface of at least one of the pair of side walls. The groove extends in a direction from the first bottom wall toward the second bottom wall.

[0007] The main wall of the case can be in close contact with the electrode body. On the other hand, a space tends to be easily formed between the side wall of the case and the electrode body. The space can be a flow path for the electrolyte. A groove is formed on the surface of the side wall. It is expected that the electrolyte will penetrate into the groove by capillary action, thereby promoting the flow of the electrolyte. In other words, it is expected that the injection property will be improved. Furthermore, since the groove is formed on the surface of the case, it is thought that it is unlikely to affect the storage space of the electrode body.

[0008] 2. The storage cell described in "1" above may include, for example, the following configuration. The storage cell further includes a current collecting member and an external terminal. The external terminal is provided on the case. The current collecting member connects the electrode body and the external terminal. At least a portion of the current collecting member is disposed between at least one of the pair of side walls and the electrode body.

[0009] By disposing the current collecting member between the side wall of the case and the electrode body, it is expected that the energy density of the electricity storage cell will be improved.

[0010] 3. The storage cell according to the above item "1" or "2" may include, for example, the following configuration: Within the case, each of the pair of main walls has a flat surface.

[0011] The flat surface of the main wall indicates that the main wall does not have any grooves. The flat surface of the main wall allows the main wall and the electrode body to come into close contact with each other. For example, when the main wall is pressed by the restraining member, it is expected that an appropriate surface pressure is applied to the electrode body.

[0012] 4. An electric storage cell according to an aspect of the present disclosure includes, for example, the following configuration. The electric storage cell includes a case, an electrode body, an electrolyte, a current collecting member, and an external terminal. The case houses the electrode body and the electrolyte. The case has a first bottom wall, a peripheral wall, and a second bottom wall. The second bottom wall faces the first bottom wall. The peripheral wall connects the first bottom wall and the second bottom wall. The peripheral wall includes a pair of main walls and a pair of side walls. The pair of main walls face each other. The pair of side walls face each other. The pair of side walls connect the pair of main walls. Each of the pair of main walls has an area larger than each of the pair of side walls. In the case, a groove is formed on a surface of at least one of the pair of side walls. The groove extends in a direction from the first bottom wall toward the second bottom wall. In the case, the surface of each of the pair of main walls is flat. The current collecting member connects the electrode body and the external terminal. At least a portion of the current collecting member is disposed between at least one of the pair of side walls and the electrode body.

[0013] Hereinafter, an embodiment of the present disclosure (hereinafter, may be abbreviated 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-restrictive. The technical scope of the present disclosure includes all modifications within the meaning and scope equivalent to the description of the claims. For example, it is also originally intended that any configuration may be extracted from the present embodiment and arbitrarily combined.

[0014] Geometric terms should not be interpreted in a strict sense. Examples of geometric terms include "parallel," "perpendicular," and the like. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms may include, for example, tolerances, errors, and the like in design, work, and manufacturing. The dimensional relationships in each figure may not match the actual dimensional relationships. The dimensional relationships in each figure may be changed to help the reader understand. For example, the length, width, thickness, and the like may be changed. Furthermore, some configurations may be omitted. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic perspective view showing an example of a storage cell according to the present embodiment. [Diagram 2] 1 is a first schematic cross-sectional view showing an example of a storage cell in the present embodiment. [Diagram 3] 4 is a second schematic cross-sectional view showing an example of a storage cell in the present embodiment. FIG. [Figure 4] FIG. 2 is a schematic cross-sectional view showing an example of an electrode body in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1. Energy storage cell FIG. 1 is a schematic perspective view showing an example of a storage cell in this embodiment. The storage cell 1 may have, for example, a height direction, a width direction, and a thickness direction. The height direction, width direction, and thickness direction are perpendicular to each other. The "height direction" is the H direction in FIG. 1, etc. The "width direction" is the W direction in FIG. 1, etc. The "thickness direction" is the T direction in FIG. 1, etc. The height direction may be parallel to the vertical direction, for example. The width direction and the thickness direction may be parallel to the horizontal direction, for example. "Height" indicates the dimension in the height direction. "Width" indicates the dimension in the width direction. "Thickness" indicates the dimension in the thickness direction, or the thickness of an object.

[0017] Fig. 2 is a first schematic cross-sectional view showing an example of a storage cell in this embodiment. Fig. 2 shows a cross section perpendicular to the T direction. The storage cell 1 includes a case 200, an electrode body 100, and an electrolyte (not shown). The electrolyte is a liquid electrolyte. The electrolyte may include, for example, an organic solvent and a lithium salt.

[0018] 2. Case The case 200 houses the electrolyte and the electrode body 100. The case 200 may be sealed. The case 200 may be sealed. The case 200 may be a single object. The case 200 may be composed of a plurality of members. The case 200 may include, for example, a can 210 and a lid 220. The can 210 has an opening. The opening opens in the H direction. The opening may open, for example, vertically upward. The can 210 may be made of, for example, a metal. The can 210 may include, for example, Al or the like. The can 210 may include, for example, a second bottom wall 212 and a peripheral wall 214. The second bottom wall 212 may be, for example, flat. The planar shape of the second bottom wall 212 may be, for example, rectangular. The peripheral wall 214 stands up from the second bottom wall 212. The peripheral wall 214 may be, for example, a square tube. The width of the peripheral wall 214 may be greater than the thickness of the peripheral wall 214. The height of the peripheral wall 214 may be greater than the thickness of the peripheral wall 214. Note that the "thickness of the peripheral wall 214" here refers to the outer dimension of the case 200 in the T direction.

[0019] The lid 220 closes the opening of the can 210. The lid 220 constitutes a first bottom wall. The second bottom wall 212 faces the first bottom wall (lid 220). The peripheral wall 214 connects the first bottom wall and the second bottom wall 212. For example, the peripheral wall 214 may be welded to the lid 220. The lid 220 may be, for example, flat. The lid 220 may be, for example, made of metal. The lid 220 may include, for example, Al, etc. The lid 220 may include, for example, a pressure release valve 222, a sealing member 224, etc.

[0020] The pressure release valve 222 may be disposed, for example, near the center of the lid 220. The pressure release valve 222 releases the internal pressure of the case 200. When the internal pressure reaches or exceeds a set value, the pressure release valve 222 can be opened. The sealing member 224 seals the liquid injection hole 221. An electrolyte can be injected from the liquid injection hole 221.

[0021] FIG. 3 is a second schematic cross-sectional view showing an example of a storage cell in this embodiment. FIG. 3 shows a cross section perpendicular to the H direction. The peripheral wall 214 includes a pair of main walls 214a and a pair of side walls 214b. The pair of main walls 214a face each other. The pair of side walls 214b face each other. The pair of side walls 214b connect the pair of main walls 214a. The main wall 214a has a larger area than the side walls 214b. In the case 200, a groove 10 is formed on at least one surface of the pair of side walls 214b. The groove 10 may be formed on each surface of the pair of side walls 214b. The groove 10 may be formed on one surface of the pair of side walls 214b.

[0022] The groove 10 extends in the H direction along the surface of the side wall 214b. That is, the groove 10 extends in a direction from the first bottom wall (lid 220) toward the second bottom wall 212. Alternatively, the groove 10 extends in a direction from the second bottom wall 212 toward the first bottom wall. The groove 10 may extend from the first bottom wall to the second bottom wall 212. The groove 10 may extend continuously. The groove 10 may extend intermittently. The groove 10 may be formed by, for example, cutting, laser processing, or the like.

[0023] The surface of the main wall 214a may also be formed with grooves 10. The surface of the main wall 214a may be flat.

[0024] The groove 10 may be either a single groove or a plurality of grooves 10. The plurality of grooves 10 may extend parallel to each other. Each of the plurality of grooves 10 may extend, for example, linearly.

[0025] The groove 10 may have any cross-sectional shape. The cross-sectional shape of the groove 10 may be, for example, V-shaped, U-shaped, rectangular, or trapezoidal. The width 10w of the groove 10 may be, for example, 10 to 1000 μm, 100 to 500 μm, or 300 to 500 μm. The ratio of the depth 10d of the groove 10 to the thickness of the side wall 214b may be, for example, 0.1 to 0.9, or 0.3 to 0.7. The pitch 10p between adjacent grooves 10 may be, for example, 0.1 to 10 mm. The shapes and sizes of the multiple grooves 10 may all be the same or may be different from each other.

[0026] 3. Electrode body The electrode body 100 may have, for example, a cubic outer shape. The electrode body 100 may have, for example, a rectangular parallelepiped outer shape. The electrode body 100 may have, for example, a flat rectangular parallelepiped shape. The electrode body 100 may be covered with, for example, an insulating film (not shown).

[0027] The "first aspect ratio" refers to the ratio of the width to the height in the electrode body 100. The first aspect ratio may be, for example, 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more, 5 or more, or 10 or more. The first aspect ratio may be, for example, 10 or less, 5 or less, 3 or less, 2.5 or less, 2 or less, or 1.5 or less. The "second aspect ratio" refers to the ratio of the thickness to the height in the electrode body 100. The second aspect ratio may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.5 or more, or 1 or more. The second aspect ratio may be, for example, 1 or less, 0.5 or less, 0.3 or less, or 0.2 or less.

[0028] The electrode body 100 may have any structure. The electrode body 100 may be, for example, a wound type. The electrode body 100 may be, for example, a laminated type.

[0029] FIG. 4 is a schematic cross-sectional view showing an example of an electrode assembly in this embodiment. The electrode assembly 100 in FIG. 4 is a laminated type. The electrode assembly 100 includes one or more first electrodes 110, one or more second electrodes 120, and one or more separators 130. In the T direction, the first electrodes 110 and the second electrodes 120 are alternately laminated. That is, the T direction of the storage cell 1 is parallel to the lamination direction of the first electrodes 110 and the second electrodes 120. The number of the first electrodes 110 and the second electrodes 120 may be any of 2 or more, 5 or more, 10 or more, 50 or more, or 100 or more. The number of the first electrodes 110 and the second electrodes 120 may be any of 200 or less, 100 or less, 50 or less, 10 or less, or 5 or less.

[0030] The second electrode 120 has a different polarity than the first electrode 110. For example, the first electrode 110 may be a positive electrode and the second electrode 120 may be a negative electrode. For example, the first electrode 110 may be a negative electrode and the second electrode 120 may be a positive electrode.

[0031] The first electrode 110 may include, for example, a first current collector 112 and a first active material layer 114. The first current collector 112 may include, for example, a metal foil or the like. The metal foil may include, for example, Al, Cu, Ni, Ti, Fe, or the like. The first active material layer 114 is disposed on a surface of the first current collector 112. The first active material layer 114 may be disposed on only one side of the first current collector 112. The first active material layer 114 may be disposed on both sides of the first current collector 112. The first active material layer 114 includes a positive electrode active material or a negative electrode active material. The positive electrode active material may include, for example, a lithium nickel composite oxide, or the like. The negative electrode active material may include, for example, graphite, SiO, Si, or the like.

[0032] The second electrode 120 may include, for example, a second current collector 122 and a second active material layer 124. The second current collector 122 may include, for example, a metal foil or the like. The second active material layer 124 is disposed on a surface of the second current collector 122. The second active material layer 124 may be disposed on only one side of the second current collector 122. The second active material layer 124 may be disposed on both sides of the second current collector 122. The second active material layer 124 includes a positive electrode active material or a negative electrode active material. The second active material layer 124 may have the same area as the first active material layer 114, or may have a different area. For example, the area of ​​the second active material layer 124 may be larger than the area of ​​the first active material layer 114. The ratio of the area of ​​the second active material layer 124 to the area of ​​the first active material layer 114 may be, for example, any of 1.01 or more, 1.05 or more, or 1.1 or more. The ratio of the area of ​​the second active material layer 124 to the area of ​​the first active material layer 114 may be, for example, any of 1.1 or less, 1.05 or less, or 1.01 or less.

[0033] The separator 130 has electrical insulation properties. The separator 130 is porous. The separator 130 may include, for example, a microporous film made of polyolefin. The thickness of the separator 130 may be, for example, 5 to 50 μm, 5 to 30 μm, or 5 to 15 μm. The separator 130 separates the first electrode 110 from the second electrode 120. The separator 130 may be, for example, two or more sheets. For example, the separator 130 may be inserted between each of the first electrode 110 and the second electrode 120.

[0034] Separator 130 may be, for example, a single sheet. For example, separator 130 may include zigzag fold portion 135. Separator 130 is folded in a zigzag shape at zigzag fold portion 135. The zigzag shape may also be expressed as, for example, a "bellows shape" or an "accordion shape."

[0035] The zigzag fold portion 135 includes a flat portion 131 and a folded portion 132. In the flat portion 131, the separator 130 extends in a flat shape. In the folded portion 132, the separator 130 is folded. The folded portion 132 is disposed at both ends in the H direction. The separator 130 is folded so as to alternately sandwich the first electrode 110 or the second electrode 120. The flat portion 131 sandwiches the first electrode 110 or the second electrode 120. The separator 130 may further include, for example, an outer peripheral portion 136. The outer peripheral portion 136 may be wound so as to wrap the zigzag fold portion 135. Note that the zigzag fold portion may be formed by folding the separator 130 at both ends in the W direction.

[0036] 4.Other The energy storage cell 1 further includes external terminals 300. The pair of external terminals 300 are fixed to the lid 220. The external terminals 300 are connected to the first electrode 110 or the second electrode 120. The external terminals 300 may be made of metal, for example. The external terminals may contain Al, Cu, Ni, or the like. The external terminals 300 may have, for example, a rectangular parallelepiped shape. The external terminals 300 may be connected to a bus bar (not shown).

[0037] The energy storage cell 1 further includes a current collecting member. The connecting member 400 constitutes the current collecting member. The pair of connecting members 400 connects the electrode tab (electrode body 100) and the external terminal 300. The electrode tab indicates the first electrode tab 116 or the second electrode tab 126. The two connecting members 400 may have substantially the same structure.

[0038] The connecting member 400 may include, for example, a current collecting tab 410, a sub-tab 420, and a connecting pin 430. The sub-tab 420 is disposed between the side wall 214b and the electrode body 100. That is, at least a part of the current collecting member is disposed between at least one of the pair of side walls 214b and the electrode body 100. The current collecting tab 410 includes a side portion 412 and an upper portion 414. The side portion 412 is located on a side of the electrode body 100 in the W direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends from an upper end of the side portion 412 toward the inside in the W direction.

[0039] The sub-tab 420 connects the electrode tabs to the current collecting tab 410. The sub-tab 420 may include a first end 422 and a second end 424. The first end 422 is connected to the electrode tabs. The second end 424 is connected to the side portion 412.

[0040] The connecting pin 430 connects the current collecting tab 410 to the external terminal 300. The connecting pin 430 connects the upper portion 414 to the external terminal 300. For example, a lower end of the connecting pin 430 may be inserted into a through hole provided in the upper portion 414.

[0041] The insulating member 500 insulates the case 200 from the connecting member 400. The insulating member 500 may include a first portion 510, a second portion 520, a third portion 530, and a fourth portion 540, for example.

[0042] The first part 510 is fixed to the upper surface of the lid 220. The first part 510 is disposed between the lid 220 and the external terminal 300. The second part 520 is fixed to the lower surface of the lid 220. The second part 520 is disposed between the lid 220 and the upper part 414. The second part 520 is disposed between the lid 220 and a lower part of the connecting pin 430. The third part 530 is disposed between the connecting pin 430 and the lid 220. The third part 530 is cylindrical. The third part 530 surrounds the connecting pin 430. The first part 510, the second part 520 and the third part 530 are provided with through holes. The connecting pin 430 is inserted through the through holes.

[0043] The fourth part 540 is plate-shaped. It is fixed to the lower surface of the upper part 414. The fourth part 540 is disposed above the electrode body 100. In the fourth part 540, a through hole is provided below the pressure release valve 222. In the fourth part 540, a through hole is also provided below the liquid injection hole 221. [Explanation of symbols]

[0044] 1 storage cell, 10 groove, 10d depth, 10p pitch, 10w width, 100 electrode body, 110 first electrode, 112 first current collector, 114 first active material layer, 116 first electrode tab, 120 second electrode, 122 second current collector, 124 second active material layer, 126 second electrode tab, 130 separator, 131 flat portion, 132 folded portion, 135 zigzag portion, 136 outer periphery, 200 case, 210 can, 212 second bottom wall, 214 peripheral wall, 214a main wall, 214b side wall, 220 lid, 221 liquid injection hole, 222 pressure release valve, 224 sealing member, 300 external terminal, 400 connecting member, 410 current collecting tab, 412 side portion, 414 Upper portion, 420, subtab, 422, first end, 424, second end, 430, connecting pin, 500, insulating member, 510, first part, 520, second part, 530, third part, 540, fourth part.

Claims

1. The battery includes a case, an electrode body, and an electrolyte. The case accommodates the electrode body and the electrolyte, The case has a first bottom wall, a peripheral wall, and a second bottom wall; The second bottom wall faces the first bottom wall, The peripheral wall connects the first bottom wall and the second bottom wall, The peripheral wall includes a pair of main walls and a pair of side walls, The pair of main walls face each other, The pair of side walls face each other, the pair of side walls connect the pair of main walls, Each of the pair of main walls has an area larger than each of the pair of side walls, A groove is formed in a surface of at least one of the pair of side walls in the case, and The groove extends in a direction from the first bottom wall toward the second bottom wall. Energy storage cell.

2. Further including a current collecting member and an external terminal; The external terminal is provided on the case, The current collecting member connects the electrode body and the external terminal, and At least a portion of the current collecting member is disposed between at least one of the pair of side walls and the electrode body. The storage cell according to claim 1 .

3. In the case, the surfaces of each of the pair of main walls are flat. The storage cell according to claim 1 or 2.

4. The battery includes a case, an electrode body, an electrolyte, a current collecting member, and an external terminal. The case accommodates the electrode body and the electrolyte, The case has a first bottom wall, a peripheral wall, and a second bottom wall; The second bottom wall faces the first bottom wall, The peripheral wall connects the first bottom wall and the second bottom wall, The peripheral wall includes a pair of main walls and a pair of side walls, The pair of main walls face each other, The pair of side walls face each other, the pair of side walls connect the pair of main walls, Each of the pair of main walls has an area larger than each of the pair of side walls, A groove is formed in a surface of at least one of the pair of side walls in the case, The groove extends in a direction from the first bottom wall toward the second bottom wall, In the case, the surface of each of the pair of main walls is flat, The current collecting member connects the electrode body and the external terminal, and At least a portion of the current collecting member is disposed between at least one of the pair of side walls and the electrode body. Energy storage cell.

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