Energy 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 a storage battery cell.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2009-301892 discloses a porous material that surrounds the electrode body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It has been proposed to dispose a porous material around the electrode body within a case. The electrolytic solution can penetrate into the porous member. Improvement in liquid injection property is expected by the arrangement of the porous member. However, since the porous material reduces the accommodation space of the electrode body, there is a possibility that the energy density of the storage battery cell decreases.

[0005] An object of the present disclosure is to improve the liquid injection property.

Means for Solving the Problems

[0006] 1. A storage cell in one aspect of the present disclosure includes, for example, the following configuration: The storage cell includes a case, electrodes, and an electrolyte. The case houses the electrodes and the electrolyte. The case has a first bottom wall, a periphery wall, and a second bottom wall. The second bottom wall faces the first bottom wall. The periphery wall connects the first bottom wall and the second bottom wall. The periphery 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 a larger area than each of the pair of side walls. A groove is formed on at least one surface of the pair of side walls within the case. 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 form between the side wall of the case and the electrode body. This space can serve as a flow path for the electrolyte. Grooves are formed on the surface of the side wall. It is expected that the electrolyte will permeate into the grooves due to capillary action, thereby promoting the flow of the electrolyte. In other words, an improvement in the pouring process can be expected. Furthermore, since the grooves are formed on the surface of the case, they are considered to have little impact on the space required to house the electrode body.

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

[0009] By placing a current collector between the side wall of the case and the electrode body, an improvement in the energy density of the energy storage cell is expected.

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

[0011] The flat surface of the main wall indicates the absence of grooves in the main wall. The flatness of the main wall allows for close contact between the main wall and the electrode body. For example, when the main wall is pressed by a restraining member, it is expected that an appropriate surface pressure will be applied to the electrode body.

[0012] 4. A storage cell in one aspect of the present disclosure includes, for example, the following configuration: The storage cell includes a case, electrodes, an electrolyte, a current collector, and external terminals. The case houses the electrodes and the electrolyte. The case has a first bottom wall, a periphery wall, and a second bottom wall. The second bottom wall faces the first bottom wall. The periphery wall connects the first bottom wall and the second bottom wall. The periphery 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 a larger area than each of the pair of side walls. A groove is formed on at least one surface of the pair of side walls within the case. The groove extends in a direction from the first bottom wall toward the second bottom wall. Within the case, the surface of each of the pair of main walls is flat. The current collector connects the electrodes to the external terminals. At least a portion of the current collector is positioned between at least one of a pair of side walls and the electrode body.

[0013] Embodiments of the present disclosure (which may be abbreviated as "Embodiments") are described below. However, these embodiments do not limit the technical scope of the present disclosure. These embodiments are illustrative in all respects. These embodiments are non-restrictive. The technical scope of the present disclosure includes all modifications within the meaning and scope equivalent to the claims. For example, it is intended from the outset that any configuration may be extracted from these embodiments and combined in any way.

[0014] Geometric terms should not be interpreted strictly. Examples of geometric terms include "parallel," "perpendicular," and "orthogonal." For example, "parallel" may deviate slightly from its strict meaning. Geometric terms may include tolerances and errors in design, operation, and manufacturing. Dimensional relationships in each diagram may not match actual dimensions. Dimensional relationships in each diagram may be altered to aid the reader's understanding. For example, length, width, and thickness may be changed. Furthermore, some components may be omitted. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic perspective view showing an example of a storage cell in this embodiment. [Figure 2] This is a first schematic cross-sectional view showing an example of a storage cell in this embodiment. [Figure 3] This is a second schematic cross-sectional view showing an example of a storage cell in this embodiment. [Figure 4] This is a schematic cross-sectional view showing an example of an electrode body in this embodiment. [Modes for carrying out the invention]

[0016] 1. Energy storage cell Figure 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 orthogonal to each other. The "height direction" is the H direction in Figure 1, etc. The "width direction" is the W direction in Figure 1, etc. The "thickness direction" is the T direction in Figure 1, etc. The height direction may be, for example, parallel to the vertical direction. The width direction and thickness direction may be, for example, parallel to the horizontal direction. "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 the object.

[0017] Figure 2 is a first schematic cross-sectional view showing an example of a storage cell in this embodiment. Figure 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 Case 200 houses the electrolyte and electrode body 100. Case 200 may be sealed. Case 200 may be a single object. Case 200 may be composed of multiple members. Case 200 may include, for example, a can 210 and a lid 220. Can 210 has an opening. The opening is open in the H direction. The opening may be open vertically upward, for example. Can 210 may be made of, for example, metal. Can 210 may contain, for example, Al. 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, a flat plate. The planar shape of the second bottom wall 212 may be, for example, a rectangle. The peripheral wall 214 rises from the second bottom wall 212. The peripheral wall 214 may be, for example, a rectangular 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 also be greater than the thickness of the peripheral wall 214. Here, "thickness of the peripheral wall 214" refers to the external dimension of the case 200 in the T direction.

[0019] The lid 220 seals the opening of the can 210. The lid 220 constitutes the 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, a flat plate. The lid 220 may be, for example, made of metal. The lid 220 may contain, for example, Al. The lid 220 may include, for example, a pressure relief valve 222 and a sealing member 224.

[0020] The pressure relief valve 222 may be disposed, for example, near the center of the lid 220. The pressure relief valve 222 releases the internal pressure of the case 200. When the internal pressure becomes equal to or greater than the set value, the pressure relief valve 222 can be opened. The sealing member 224 seals the liquid injection hole 221. Electrolyte can be injected through the liquid injection hole 221.

[0021] FIG. 3 is a second schematic cross-sectional view showing an example of the storage cell in the present embodiment. In FIG. 3, a cross-section perpendicular to the H direction is shown. 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 wall 214b. In the case 200, a groove 10 is formed on at least one surface of the pair of side walls 214b. Grooves 10 may be formed on each surface of the pair of side walls 214b. Grooves 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 the direction from the first bottom wall (lid 220) to the second bottom wall 212. Alternatively, the groove 10 extends in the direction from the second bottom wall 212 to 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 can be formed, for example, by cutting, laser processing, or the like.

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

[0024] The groove 10 may be either single or plural. 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 multiple grooves 10 may all be the same or may be different from one another.

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

[0027] The "first aspect ratio" indicates the ratio of width to 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" indicates the ratio of thickness to 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. For example, the electrode body 100 may be wound. For example, the electrode body 100 may be stacked.

[0029] Figure 4 is a schematic cross-sectional view showing an example of an electrode body in this embodiment. The electrode body 100 in Figure 4 is of the stacked type. The electrode body 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 stacked alternately. That is, the T direction of the energy storage cell 1 is parallel to the stacking direction of the first electrodes 110 and the second electrodes 120. The number of first electrodes 110 and second electrodes 120 may be 2 or more, 5 or more, 10 or more, 50 or more, or 100 or more, respectively. The number of first electrodes 110 and second electrodes 120 may be 200 or less, 100 or less, 50 or less, 10 or less, or 5 or less, respectively.

[0030] The second electrode 120 has a different polarity from the first electrode 110. For example, the first electrode 110 may be the positive electrode and the second electrode 120 may be the negative 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. The metal foil may include, for example, Al, Cu, Ni, Ti, Fe, etc. The first active material layer 114 is disposed on the 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. The negative electrode active material may include, for example, graphite, SiO, Si, etc.

[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. The second active material layer 124 is disposed on the 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 it 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, 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, 1.1 or less, 1.05 or less, or 1.01 or less.

[0033] The separator 130 has electrical insulating properties. The separator 130 is porous. The separator 130 may include, for example, a microporous membrane 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. There may be, for example, two or more separators 130. For example, one separator 130 may be inserted between the first electrode 110 and the second electrode 120.

[0034] The separator 130 may be, for example, a single sheet. For example, the separator 130 may include a zigzag section 135. In the zigzag section 135, the separator 130 is folded in a zigzag pattern. The zigzag pattern can also be described as, for example, "bellows-like" or "accordion-like."

[0035] The zigzag section 135 includes a flat section 131 and a folded section 132. In the flat section 131, the separator 130 extends in a planar manner. In the folded section 132, the separator 130 is folded back. The folded sections 132 are located at both ends in the H direction. The separator 130 is folded back so as to alternately sandwich the first electrode 110 or the second electrode 120. The flat section 131 sandwiches the first electrode 110 or the second electrode 120. The separator 130 may further include, for example, an outer peripheral section 136. The outer peripheral section 136 may be wound around the zigzag section 135. The zigzag section may also be formed at both ends in the W direction by folding back the separator 130.

[0036] 4. Others The energy storage cell 1 further includes external terminals 300. A pair of external terminals 300 are fixed to the cover 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, for example, metal. The external terminals may contain Al, Cu, Ni, etc. The external terminals 300 may have, for example, a rectangular parallelepiped shape. The external terminals 300 may be connected to a busbar (not shown).

[0037] The energy storage cell 1 further includes a current collector. The connecting member 400 constitutes the current collector. A pair of connecting members 400 are connected to electrode tabs (electrode bodies 100) and external terminals 300. The electrode tabs refer to 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 positioned between the side wall 214b and the electrode body 100. That is, at least a portion of the current-collecting member is positioned between at least one of the pair of side walls 214b and the electrode body 100. The current-collecting tab 410 includes a lateral portion 412 and an upper portion 414. The lateral portion 412 is located laterally to the electrode body 100 in the W direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends inward in the W direction from the upper end of the lateral portion 412.

[0039] The sub-tab 420 connects multiple electrode tabs to the current collection 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 multiple electrode tabs. The second end 424 is connected to the lateral portion 412.

[0040] The connecting pin 430 connects the current collection tab 410 to the external terminal 300. The connecting pin 430 also connects the upper portion 414 to the external terminal 300. For example, the lower end of the connecting pin 430 may be inserted through 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, for example, a first part 510, a second part 520, a third part 530, and a fourth part 540.

[0042] Part 1 510 is fixed to the upper surface of the lid 220. Part 1 510 is positioned between the lid 220 and the external terminal 300. Part 2 520 is fixed to the lower surface of the lid 220. Part 2 520 is positioned between the lid 220 and the upper part 414. Part 2 520 is positioned between the lid 220 and the lower part of the connecting pin 430. Part 3 530 is positioned between the connecting pin 430 and the lid 220. Part 3 530 is cylindrical. Part 3 530 surrounds the connecting pin 430. Parts 1 510, 2 520, and 3 530 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 positioned above the electrode body 100. A through hole is provided in the fourth part 540 below the pressure relief valve 222. A through hole is also provided in the fourth part 540 below the liquid injection hole 221. [Explanation of symbols]

[0044] 1 Energy 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 section, 132 Folded section, 135 Zigzag section, 136 Outer circumference, 200 Case, 210 Can, 212 Second bottom wall, 214 Peripheral wall, 214a Main wall, 214b Side wall, 220 Lid, 221 Injection hole, 222 Pressure relief valve, 224 Sealing member, 300 External terminal, 400 Connecting member, 410 Current collector tab, 412 Side section, 414 Upper section, 420 sub-tab, 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. Includes case, 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 is opposite the first bottom wall, The aforementioned 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 a larger area than each of the pair of side walls. Within the case, a groove is formed on at least one surface of the pair of side walls, The groove extends from the first bottom wall to the second bottom wall in the direction from the first bottom wall to the second bottom wall, Within the case, the inner surfaces of each of the pair of main walls are flat. In the electrode body, electrodes are stacked in the direction normal to the pair of main walls. The pair of main walls and the main surface of the electrode body are in close contact. Energy storage cell.

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

3. The ratio of the width to the height of the electrode body is 2 or more and 10 or less. The ratio of the thickness of the electrode body to its height is 0.1 or more and 0.5 or less. The height mentioned above indicates the dimension in the normal direction of the first bottom wall and the second bottom wall. The width refers to the dimension in the normal direction of the pair of side walls. The aforementioned thickness indicates the dimension in the normal direction of the pair of main walls. The energy storage cell according to claim 1 or claim 2.

4. Includes case, electrode body, electrolyte, current collector and external terminals, 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 is opposite the first bottom wall, The aforementioned 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 a larger area than each of the pair of side walls. Within the case, a groove is formed on at least one surface of the pair of side walls. The groove extends from the first bottom wall to the second bottom wall in the direction from the first bottom wall to the second bottom wall, Within the case, the inner surfaces of each of the pair of main walls are flat. In the electrode body, electrodes are stacked in the direction normal to the pair of main walls. The pair of main walls and the main surface of the electrode body are in close contact. The current collector member connects the electrode body and the external terminal, At least a portion of the current collector is disposed between at least one of the pair of side walls and the electrode body. Energy storage cell.

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