Battery

Abstract

The utility model provides a battery capable of inhibiting liquid injection performance reduction. This battery is provided with: an electrode laminate in which electrode bodies are laminated; and a liquid injection port for injecting an electrolyte solution into the internal space of the electrode laminate on a side surface in the lamination direction of the electrode laminate, the liquid injection port having a wave shape in which a wide portion and a narrow portion are alternately repeated when viewed from the liquid injection direction.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a battery. BACKGROUND

[0002] A conventional battery has an electrode body in which a current collector foil, a positive electrode active material layer, and a negative electrode active material layer are stacked, and a sealing body configured to cover a region of an end side of the current collector foil, and has a liquid injection port for injecting an electrolyte from a side surface of the sealing body.

[0003] For example, Japanese Patent Application Publication No. 2020-021544 discloses a bipolar battery having an electrode stack, and a sealing body that surrounds the electrode stack and seals a plurality of internal spaces formed between electrodes adjacent in a stacking direction, respectively, a plurality of communication holes that communicate with each of the plurality of internal spaces are provided in a side surface along the stacking direction of the sealing body, at least a portion of a part of an end portion of the sealing body on one side in the stacking direction in which a communication hole that communicates with an internal space of an outermost layer on the one side overlaps from the stacking direction is provided with a first protrusion, and at least a portion of a part of an end portion of the sealing body on the other side in the stacking direction in which a communication hole that communicates with an internal space of an outermost layer on the other side overlaps from the stacking direction is provided with a second protrusion. SUMMARY

[0004] An object of the present disclosure is to provide a battery capable of suppressing a decrease in liquid injection property.

[0005] A battery of a first aspect of the present disclosure has: an electrode stack stacked with electrode bodies; and a liquid injection port for injecting an electrolyte into an internal space of the electrode stack on a side surface with respect to a stacking direction of the electrode stack, the liquid injection port being in a wavy shape in which a portion with a wide width and a portion with a narrow width are alternately repeated as viewed from a liquid injection direction.

[0006] A battery of a second aspect of the present disclosure is the battery of the first aspect, further having a liquid injection port frame configured to surround the liquid injection port, the liquid injection port being in a shape in which walls opposite to each other at the portion with the narrow width do not contact each other in a state in which an external force is not applied to the liquid injection port frame from the outside as viewed from the liquid injection direction.

[0007] According to the battery of the present disclosure, it is possible to suppress a decrease in liquid injection property. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 A schematic perspective view of a battery related to an embodiment of the present disclosure.

[0009] Figure 2 A schematic plan view of one face of the battery shown. Figure 1

[0010] ​Figure 3 is a schematic plan view showing a liquid injection port and a liquid injection port frame, and an enlarged view showing a portion of an end of the liquid injection port.

[0011] Figure 4 is a schematic cross-sectional view of a battery to which an embodiment of the present disclosure is applied.

[0012] Figure 5 is a schematic perspective view showing a liquid injection port and a liquid injection port frame in a conventional battery.

[0013] Figure 6 is a schematic cross-sectional view showing a state in which a liquid injection device is pressed against a liquid injection port frame of a conventional battery to inject electrolyte. DETAILED DESCRIPTION

[0014] A battery to which an embodiment of the present disclosure is applied has an electrode laminate in which electrode bodies are laminated, and a liquid injection port for injecting electrolyte into an internal space of the electrode laminate on a side surface with respect to a laminating direction of the electrode laminate. Moreover, the liquid injection port is in a wavy shape in which a portion with a wide width and a portion with a narrow width are alternately repeated as viewed from a liquid injection direction.

[0015] The liquid injection direction refers to a direction in which electrolyte travels in the liquid injection port when the electrolyte is injected into the internal space of the electrode laminate through the liquid injection port.

[0016] The battery to which an embodiment of the present disclosure is applied has, for example, an electrode body including a negative electrode, a positive electrode, a separator, and electrolyte. The battery to which an embodiment of the present disclosure is applied is, for example, suitable for a liquid battery having electrolyte in a liquid state. A liquid battery having nonaqueous electrolyte is particularly preferable. In addition, it can also be a bipolar battery having a bipolar electrode body having a positive electrode active material layer and a negative electrode active material layer on both surfaces of a current collector having the function of a positive electrode current collector and a negative electrode current collector.

[0017] The battery to which an embodiment of the present disclosure is applied will be described in detail below with reference to the drawings.

[0018] Here, the configuration of the battery to which an embodiment of the present disclosure is applied will be described taking a bipolar secondary battery as an example. In the description of the drawings, the same symbols are used for the same or equivalent elements, and repeated description is omitted.

[0019] Figure 1 is a schematic perspective view of a battery 2 to which an embodiment of the present disclosure is applied. Figure 2 is a schematic plan view showing a wall surface 16a of the battery 2 shown in Figure 1 Figure 1 ​As shown, the battery 2 has an electrode stack 15 with stacked electrode bodies and a resin sealing member 16 that seals the electrode stack 15. The electrode stack 15 is composed of multiple electrode bodies stacked with separators between them. These electrode bodies may be, for example, a stack containing multiple bipolar electrodes, a negative terminal electrode, and a positive terminal electrode.

[0020] The electrode stack 15, when viewed from the thickness direction of the battery 2 (i.e., the stacking direction, Z direction in the electrode stack 15), has a rectangular shape. Furthermore, the term "rectangular" here includes not only true rectangles (e.g., squares, etc.), but also cases where the battery as a whole has a shape close to a rectangle. Therefore, the aforementioned "rectangular" also includes, for example, shapes that are close to a rectangle but with slightly rounded corners.

[0021] Furthermore, a rectangular battery can be a rectangle with sides that are at least 1000mm long and at least 10000mm wide.

[0022] The sealing member 16 is shaped as a rectangular cylinder. The sealing member 16 is disposed on the side of the electrode stack 15 (i.e., on the side relative to the stacking direction (Z direction) of the electrode stack 15). The sealing member 16 has a plurality of primary sealing portions 22 and secondary sealing portions 23 that surround the primary sealing portions 22 from the outside along the side of the electrode stack 15 and are respectively engaged with the primary sealing portions 22. The primary sealing portions 22 are, for example, films having a predetermined thickness in the stacking direction.

[0023] The secondary sealing portion 23 is disposed on the outside of the electrode stack 15 and the primary sealing portion 22, forming the outer wall (i.e., frame) of the battery 2. The secondary sealing portion 23 extends along the entire length of the electrode stack 15 in the stacking direction. The secondary sealing portion 23 is in the shape of a rectangular frame extending axially in the stacking direction. The secondary sealing portion 23 is, for example, fused to the outer surface of the primary sealing portion 22. From the viewpoint of reducing manufacturing costs, the secondary sealing portion 23 can be formed on a portion of the outer surface of the primary sealing portion 22, or it can be formed on, for example, the wall surface 16a having the liquid injection port 30. The sealing member 16 can be a component integrally formed with the primary sealing portion 22 and the secondary sealing portion 23, that is, it can be formed in a manner where, for example, the boundary between the primary sealing portion 22 and the secondary sealing portion 23 is not clearly defined.

[0024] The primary sealing part 22 and the secondary sealing part 23 form an internal space between adjacent electrode bodies in the electrode stack 15. Figure 1 (Not shown) and the internal space is sealed. An electrolyte (not shown) containing, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent is contained within this internal space. The electrolyte, for example, permeates the separators, positive electrode, and negative electrode constituting the electrode stack 15.

[0025] likeFigure 1 and Figure 2 As shown, a plurality of liquid injection ports 30 are provided on a wall surface 16a constituting the sealing component 16. A liquid injection port frame 32 is provided on the wall surface 16a surrounding each liquid injection port 30. Each liquid injection port 30 communicates with the internal space of a different battery cell. Electrolyte is injected into the internal space of the electrode stack 15 through its respective liquid injection port 30.

[0026] In this embodiment, 24 injection ports 30 are separately arranged in four regions A1 to A4, orthogonal to the stacking direction (Z direction) and along the wall surface 16a (Y direction). Viewed from the direction opposite to the wall surface 16a (X direction), regions A1 to A4 are arranged from right to left in this order. Each region A1 to A4 is of the same size and is a region where a pressure regulating valve (not shown) is installed. Each region A1 to A4 has six injection ports 30.

[0027] In region A1, two injection ports 30 are arranged in each of three columns along the Y direction, with each column aligned with the stacking direction (Z direction). In region A2, six injection ports 30 are arranged with each of them offset downwards by one step relative to the six injection ports 30 in region A1 in the stacking direction. In region A3, six injection ports 30 are arranged with each of them offset downwards by two steps relative to the six injection ports 30 in region A1 in the stacking direction. In region A4, six injection ports 30 are arranged with each of them offset downwards by three steps relative to the six injection ports 30 in region A1. Thus, as an example in this embodiment, the 24 injection ports 30 are arranged to be point-symmetric with respect to the center of the wall 16a when viewed from the direction opposite to the wall 16a (X direction).

[0028] Here, the shape of the injection port 30 will be described.

[0029] Figure 3 This is a schematic top view showing one injection port 30 and an injection port frame 32, as well as an enlarged view showing a portion of the end of the injection port 30. (See attached image.) Figure 3 As shown, the injection port 30 is from the injection direction ( Figure 3 The shape observed (in the X direction) is a wavy shape with alternating wide regions 30A and narrow regions 30B. The injection port 30, in a state where no external force is applied (e.g., no external force is applied to the injection port frame 32), has a shape formed by walls 31Aa and 31Ab. That is, it has a shape in which opposing walls 31Aa and 31Ab in the narrow region 30B do not contact each other. Furthermore, the injection direction refers to the direction in which the electrolyte travels within the injection port 30 when electrolyte is injected into the internal space of the electrode stack 15 through the injection port 30.

[0030] Here, a method of forming the injection port 30 having a wavy shape in which the wide region portion 30A having a wide width and the narrow region portion 30B having a narrow width are alternately repeated will be described. Figure 3 In the past, the injection port has been formed by using a flat nest on both the front and back surfaces, and a flat slit-shaped cross-sectional shape has been obtained. In contrast, the present disclosure is capable of obtaining a battery having a wavy cross-sectional shape in which the wide region portion 30A having a wide width and the narrow region portion 30B having a narrow width are alternately repeated by forming the injection port 30 using a nest having a wavy cross-sectional shape. Figure 3 A battery having an injection port 30 having a wavy cross-sectional shape in which the wide region portion 30A having a wide width and the narrow region portion 30B having a narrow width are alternately repeated, as shown in FIG. 1.

[0031] As shown in FIG. 2, the shape of the injection port 30 of the battery according to the embodiment of the present disclosure, as viewed from the injection direction, is a wavy shape in which the portion having a wide width (wide region portion 30A) and the portion having a narrow width (narrow region portion 30B) are alternately repeated, and thus the decrease in the injection property can be suppressed. Figure 3

[0032] Here, a conventional battery will be described using FIGS. 3 and 4. Figure 5 and Figure 6 A schematic perspective view showing one injection port 130 and an injection port frame 132 in a conventional battery is shown in FIG. 3. Figure 5 A schematic cross-sectional view showing a state in which a gasket 34 is pressed against the injection port frame 132 of the conventional battery to inject electrolyte 36 is shown in FIG. 4. Figure 6

[0033] Figure 5 The conventional battery shown in FIG. 5 has an injection port 130 on the wall surface 16a of the sealing member 16. The injection port 130 has a flat slit shape. An injection port frame 132 having an injection port frame end 132a and an injection port frame wall 132b is provided around the injection port 130. In order to inject electrolyte 36 into the internal space of the electrode laminate through the injection port 130, as shown in FIG. 6, if the gasket 34 as an injection device is pressed against the injection port frame 132 from the injection port frame end 132a side, the injection port frame 132 is deformed by the pressure. In addition, the pressure applied to the electrolyte 36 at the time of injection also deforms the injection port frame 132. Furthermore, the injection port 130 is flat and slit-shaped in a state in which no external force is applied from the outside, but is deformed into the shape shown as injection port 130X by the pressure of the gasket 34 or the like. Therefore, when the injection port 130X is subjected to pressure, the opposing walls come into contact with each other and are occluded, resulting in a decrease in the injection property. Figure 6

[0034] ​​​In contrast, the shape of the electrolyte injection port of the battery according to the embodiment of the present disclosure, as viewed from the direction of electrolyte injection, is a wavy shape in which a portion with a wide width and a portion with a narrow width are alternately repeated. Therefore, even if the electrolyte injection port 30 is deformed by an external force, the electrolyte injection port 30 will maintain the shape formed by the wall 31Ba and the wall 31Bb, as shown in FIG. 1. Therefore, the wall 31Ba and the wall 31Bb are in contact with each other at the narrow region portion 30B with a narrow width, but the wall 31Ba and the wall 31Bb are not in contact with each other at the wide region portion 30A with a wide width. That is, the entire electrolyte injection port 30 is not occluded, and the area for electrolyte injection can be ensured. Thus, the decrease in the electrolyte injection property is suppressed in the battery according to the embodiment of the present disclosure. Figure 3

[0035] In addition, the case where one electrolyte injection port 30 is provided in one electrolyte injection port frame 32 is shown in FIGS. 1 to 3, but the present disclosure is not limited to this case. Two or more electrolyte injection ports can be provided in one electrolyte injection port frame, for example. For example, a plurality of electrolyte injection ports can be arranged intermittently in a straight line in one electrolyte injection port frame. In other words, the case where a plurality of electrolyte injection ports are arranged in a straight line and a column portion is provided between the plurality of electrolyte injection ports to divide the electrolyte injection ports from each other can be adopted. By adopting the case where a column portion is provided between a plurality of electrolyte injection ports, the electrolyte injection ports are less likely to be deformed by an external force. Therefore, even in the case where an external force is applied from the outside, it is easier to suppress the occlusion of the electrolyte injection ports when electrolyte is injected through the electrolyte injection ports, and thus a more excellent electrolyte injection property can be achieved. Figure 2 Figure 3 Next, an example of the configuration of the electrode stack 15 in the battery 2 shown in FIG. 1 will be described with reference to FIG. 2.

[0036] The battery 2 shown in FIG. 1 has a configuration including a stack of a plurality of bipolar electrodes, a negative terminal electrode, and a positive terminal electrode. In addition, in FIG. 2, "upper surface" means the upper side of the drawing, and "lower surface" means the lower side of the drawing. Figure 4 Figure 1 Figure 4 A schematic cross-sectional view of the battery 2 is shown in FIG. 1. The battery 2 has a configuration in which a plurality of battery cells (for example, 24 battery cells) are stacked (a plurality of battery cell configuration). The battery 2 has an electrode stack 15. A plurality of (in this case, 24) electrolyte injection ports (not shown in FIG. 1) that communicate with respective internal spaces V are opened in one side surface of the module main body 11. Figure 4

[0037] Figure 4 A schematic cross-sectional view of the battery 2 is shown in FIG. 1. The battery 2 has a configuration in which a plurality of battery cells (for example, 24 battery cells) are stacked (a plurality of battery cell configuration). The battery 2 has an electrode stack 15. A plurality of (in this case, 24) electrolyte injection ports (not shown in FIG. 1) that communicate with respective internal spaces V are opened in one side surface of the module main body 11. Figure 4

[0038] ​​​​​​The module main body 11 has an electrode stack 15 and a sealing member 16. The electrode stack 15 has a plurality of electrodes (bipolar electrode 13, positive terminal electrode 20, and negative terminal electrode 21) stacked with the separator 14 interposed therebetween. The sealing member 16 is provided so as to surround the electrode stack 15 as viewed in the stacking direction (Z direction) of the plurality of electrodes, and seals a plurality of internal spaces V formed between the electrodes adjacent in the stacking direction, respectively.

[0039] The bipolar electrode 13 and the separator 14, for example, are rectangular in plan view. The separator 14 is disposed between the bipolar electrodes 13 adjacent in the stacking direction. The bipolar electrode 13 has an electrode plate 17 as a current collector, a positive electrode 18 formed on an upper surface 17a (one surface) of the electrode plate 17, and a negative electrode 19 formed on a lower surface 17b (the other surface) of the electrode plate 17.

[0040] The positive electrode 18 of the bipolar electrode 13 opposes the negative electrode 19 of the bipolar electrode 13 adjacent in the stacking direction with the separator 14 interposed therebetween. The negative electrode 19 of the bipolar electrode 13 opposes the positive electrode 18 of the bipolar electrode 13 adjacent in the stacking direction with the separator 14 interposed therebetween.

[0041] The positive terminal electrode 20 is disposed in the lowermost layer of the electrode stack 15. The positive terminal electrode 20 has the electrode plate 17 and the positive electrode 18 formed on the upper surface 17a of the electrode plate 17. The negative terminal electrode 21 is disposed in the uppermost layer of the electrode stack 15. The negative terminal electrode 21 has the electrode plate 17 and the negative electrode 19 formed on the lower surface 17b of the electrode plate 17. The positive electrode 18 of the positive terminal electrode 20 opposes the negative electrode 19 of the bipolar electrode 13 in the lowermost layer with the separator 14 interposed therebetween. The negative electrode 19 of the negative terminal electrode 21 opposes the positive electrode 18 of the bipolar electrode 13 in the uppermost layer with the separator 14 interposed therebetween. The electrode plates 17 of the positive terminal electrode 20 and the negative terminal electrode 21 are connected to a conductive plate (not shown) adjacent in the stacking direction.

[0042] The electrode plate 17 can be exemplified by a laminated foil of an aluminum foil and a copper foil, for example. As an example, the electrode plate 17 is a rectangular metal laminated foil in which an aluminum foil is provided on the positive electrode side and a copper foil is provided on the negative electrode side. The positive electrode 18 is formed by applying a positive electrode active material to one surface of the electrode plate 17. As the positive electrode active material, nickel hydroxide on which a cobalt (Co) oxide coating is implemented is used, for example. The negative electrode 19 is formed by applying a negative electrode active material to the other surface of the electrode plate 17. As the negative electrode active material, a hydrogen storage alloy is used, for example. The peripheral portion 17c of the electrode plate 17 is an uncoated region to which neither the positive electrode active material nor the negative electrode active material is applied.

[0043] The separator 14 is arranged between the positive electrode 18 and the negative electrode 19 to separate the positive electrode 18 and the negative electrode 19. The separator 14 is smaller than the electrode plate 17 and larger than the positive electrode 18 and the negative electrode 19 when viewed in the stacking direction. The separator 14 is formed, for example, in a sheet shape. The separator 14 is formed of a porous film composed of a polyolefin-based resin such as polyethylene (PE) or polypropylene (PP), or a nonwoven fabric or a woven fabric composed of PE, PP, or methyl cellulose, or the like. In addition, the separator 14 can be reinforced with a vinylidene fluoride resin compound or the like. In addition, the shape of the separator 14 is not particularly limited to a sheet shape, and can be a bag shape.

[0044] The sealing member 16 holds the peripheral portion 17c of each electrode plate 17 at the side surface of the electrode stack 15. The sealing member 16 has a plurality of primary sealing portions 22 provided at the peripheral portion 17c of each of the plurality of electrodes (electrode plates 17), and a secondary sealing portion 23 that surrounds the plurality of primary sealing portions 22 from the outside.

[0045] The primary sealing portion 22 is in a rectangular frame shape and is continuously provided at the entire periphery of the peripheral portion 17c of the electrode plate 17 when viewed in the stacking direction. The primary sealing portion 22 is, for example, fusion-bonded to one face of the electrode plate 17 to be hermetically joined. The primary sealing portion 22 is, for example, fusion-bonded by ultrasonic waves or heat. The primary sealing portion 22 is a film having a prescribed thickness (length in the stacking direction). A part of the inside of the primary sealing portion 22 is positioned between the peripheral portions 17c of the electrode plates 17 that are adjacent to each other in the stacking direction, and a part of the outside protrudes further outward than the end portion of the electrode plate 17. The end portions of the parts of the outside of the plurality of primary sealing portions 22 are fusion-bonded to each other. For example, the end portions of the parts of the outside of the plurality of primary sealing portions 22 are fixed to each other in a manner that the positions of the end portions coincide with each other by bringing a hot plate into contact with the end portions. However, the end portions of the parts of the outside of the plurality of primary sealing portions 22 can not be fixed to each other by fusion-bonding or the like. In this case, the secondary sealing portion 23 can enter a gap formed between the end portions of the parts of the outside of the plurality of primary sealing portions 22. In addition, the primary sealing portion 22 is also provided at the edge portion of the lower surface 17b of the electrode plate 17 of the positive electrode terminal electrode 20.

[0046] An internal space V partitioned by the electrode plate 17, the positive electrode 18, the negative electrode 19, and the primary sealing portion 22 is provided between the electrode plates 17 that are adjacent to each other in the stacking direction. Therefore, a plurality of internal spaces V are provided in the electrode stack 15. An electrolyte is injected into the internal spaces V including the inside of the separator 14. The primary sealing portion 22 seals the internal space V. Each battery cell of the battery 2 is composed of two electrode plates 17, the positive electrode 18, the negative electrode 19, the separator 14, and the primary sealing portion 22, and has the internal space V.

[0047] The secondary seal portion 23 is provided outside the electrode laminate 15 and the primary seal portion 22, and constitutes an outer wall (frame) of the battery 2. In the case of being a one-piece molded product, for example, the secondary seal portion 23 can be formed by injection molding of resin. The secondary seal portion 23 extends along the stacking direction over the entire length of the electrode laminate 15. The secondary seal portion 23 is fused (joined) to the outer surface of the primary seal portion 22, for example, by heating at the time of injection molding.

[0048] In addition, the seal member 16 can also be a member in which the primary seal portion 22 and the secondary seal portion 23 are integrally molded. For example, a pair of resin sheets can also be provided so as to sandwich the end portion of each electrode plate 17 and protrude outward beyond the end portion, the primary seal portion 22 can be formed by fusing the pair of resin sheets to each electrode plate 17, and further the secondary seal portion 23 can be formed by fusing the resin sheets protruding outward beyond the end portion of each electrode plate 17 to each other, thereby the seal member 16 in which the primary seal portion 22 and the secondary seal portion 23 are integrally molded.

[0049] The primary seal portion 22 and the secondary seal portion 23 are formed of resin such as polyethylene (PE), polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE), for example.

[0050] As the use of the battery related to the embodiments of the present disclosure, for example, a power source for a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), an electric vehicle (BEV), and the like can be cited. The battery related to the embodiments of the present disclosure can be appropriately changed in material and shape, and the like within a range not departing from the design intent in such use. The shape of the battery can be set to an arbitrary shape such as a square or a rectangular shape, for example. The battery can be a bipolar battery having a bipolar electrode body, or can be a monopolar battery.

Claims

1. A battery, characterized by, having: an electrode stack formed by stacking electrode bodies; and an injection port for injecting an electrolyte into an internal space of the electrode stack, on a side surface with respect to a stacking direction of the electrode stack, a shape of the injection port, as viewed from an injection direction, is a wavy shape in which a portion having a wide width and a portion having a narrow width are alternately repeated.

2. The battery according to claim 1, further comprising: an injection port frame disposed so as to surround the injection port, a shape of the injection port, as viewed from an injection direction, is a shape in which walls opposite to each other at the portion having the narrow width do not contact each other in a state in which an external force is not applied to the injection port frame from the outside.

Images