Battery

Abstract

To provide a battery in which a decrease in liquid injection property is suppressed.SOLUTION: A battery includes: an electrode laminate in which electrode bodies are stacked; and an injection port for injecting an electrolyte into an internal space of the electrode laminate at a side surface with respect to the stacking direction of the electrode laminate, the injection port having a wavy shape in which a wide portion and a narrow portion are alternately repeated when viewed from an injection direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Conventionally, a battery has been used that has an electrode body in which a current collecting foil, a positive electrode active material layer, and a negative electrode active material layer are laminated, and a sealing body that is arranged so as to cover an end side region of the current collecting foil, and that has a liquid injection port for injecting an electrolyte solution from the side surface of the sealing body.

[0003] For example, Patent Document 1 discloses a bipolar battery that includes an electrode stack and a sealing body that surrounds the electrode stack and seals each of a plurality of internal spaces formed between adjacent electrodes in the stacking direction, wherein a plurality of communication holes that communicate with each of the plurality of internal spaces are provided on a side surface of the sealing body along the stacking direction, and a first convex portion is provided on at least a portion of an end of the sealing body on one side in the stacking direction that overlaps with the communication hole that communicates with the internal space of the outermost layer on one side as viewed from the stacking direction, and a second convex portion is provided on at least a portion of an end of the sealing body on the other side in the stacking direction that overlaps with the communication hole that communicates with the internal space of the outermost layer on the other side as viewed from the stacking direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-021544 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a battery in which the decrease in the injection property is suppressed. [Means for solving the problem]

[0006] Means for solving the above problems include the following aspects. <1> an electrode stack in which electrode bodies are stacked; a liquid injection port for injecting an electrolyte solution into an internal space of the electrode stack, the liquid injection port being provided on a side surface of the electrode stack in a stacking direction of the electrode stack; and The battery, wherein the injection port has a wave-like shape when viewed from the injection direction, with wide portions and narrow portions alternately repeated. <2> a liquid inlet frame arranged to surround the liquid inlet, a shape of the pouring port as viewed from the pouring direction such that opposing walls at the narrow portion are not in contact with each other when no external force is applied to the pouring port frame from the outside; <1> The battery described in [Effects of the Invention]

[0007] According to the present disclosure, a battery is provided in which the deterioration of the liquid injection property is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a battery according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic plan view showing one surface of the battery shown in FIG. [Figure 3] 1 is a schematic plan view showing a liquid filling port and a liquid filling port frame, and an enlarged view showing a part of an end portion of the liquid filling port. [Figure 4] FIG. 1 is a schematic cross-sectional view of a battery according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a schematic perspective view showing a filling port and a filling port frame in a conventional battery. [Figure 6] FIG. 10 is a schematic cross-sectional view showing a state in which an electrolyte injection device is pressed against a filling port frame of a conventional battery to inject electrolyte. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Battery> A battery according to an embodiment of the present disclosure includes an electrode stack in which electrode assemblies are stacked, and a liquid inlet for injecting an electrolyte solution into an internal space of the electrode stack, the liquid inlet being provided on a side surface of the electrode stack in the stacking direction. The liquid inlet has a wavy shape when viewed from the liquid inlet direction, with wide and narrow portions alternately repeated.

[0010] The liquid pouring direction refers to the direction in which the electrolyte advances through the liquid pouring port when the electrolyte is poured into the internal space of the electrode stack through the liquid pouring port.

[0011] The electrode assembly in the battery according to the embodiment of the present disclosure includes, for example, a negative electrode, a positive electrode, a separator, and an electrolyte. The battery according to the embodiment of the present disclosure is suitable for use in, for example, a liquid battery having a liquid electrolyte. In particular, a liquid battery having a non-aqueous electrolyte is preferred. Furthermore, the battery may be a bipolar battery having a bipolar electrode assembly including a positive electrode active material layer and a negative electrode active material layer on both sides of a current collector that functions as a positive electrode current collector and a negative electrode current collector.

[0012] Hereinafter, a battery according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0013] Here, the configuration of a battery according to an embodiment of the present disclosure will be described using a bipolar secondary battery as an example. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0014] FIG. 1 is a schematic perspective view of a battery according to an embodiment of the present disclosure. FIG. 2 is a schematic plan view showing a wall surface 16a of the battery shown in FIG. 1. As shown in FIG. 1, the battery 2 includes an electrode stack 15 in which electrode assemblies are stacked, and a resin sealing member 16 that seals the electrode stack 15. The electrode stack 15 is composed of multiple electrode assemblies stacked with separators interposed between them. These electrode assemblies may include, for example, a stack of multiple bipolar electrodes, a negative terminal electrode, and a positive terminal electrode.

[0015] The electrode laminate 15 has a rectangular shape when viewed in the thickness direction of the battery 2 (i.e., the stacking direction, Z direction, in the electrode laminate 15). Note that the term "rectangular" here does not only include cases where the shape is an exact rectangle (e.g., a rectangle, a square, etc.), but also includes cases where the battery as a whole has a shape close to a rectangle. Therefore, the above-mentioned "rectangular" also includes, for example, a shape close to a rectangle with slightly rounded corners. The rectangular battery can have a length of 1000 mm or more and a width of 10000 mm or more.

[0016] The sealing member 16 has an overall rectangular cylindrical shape. The sealing member 16 is disposed on the side surface of the electrode stack 15 (i.e., the side surface in the stacking direction (Z direction) of the electrode stack 15). The sealing member 16 has a plurality of primary seal portions 22 and secondary seal portions 23 that surround the primary seal portions 22 from the outside along the side surface of the electrode stack 15 and are joined to each of the primary seal portions 22. The primary seal portions 22 are, for example, a film having a predetermined thickness in the stacking direction.

[0017] The secondary seal 23 is provided on the outside of the electrode stack 15 and the primary seal 22 and constitutes the outer wall (i.e., the housing) of the battery 2. The secondary seal 23 extends along the stacking direction over the entire length of the electrode stack 15. The secondary seal 23 has a rectangular frame shape extending axially along the stacking direction. The secondary seal 23 is welded to the outer surface of the primary seal 22, for example. From the perspective of reducing manufacturing costs, the secondary seal 23 may be formed on a portion of the outer surface of the primary seal 22, for example, on the wall surface 16a having the liquid inlet 30. The seal member 16 may be a component in which the primary seal 22 and the secondary seal 23 are integrally molded, that is, the boundary between the primary seal 22 and the secondary seal 23 may be unclear (for example).

[0018] The primary seal 22 and the secondary seal 23 form an internal space (not shown in FIG. 1 ) between adjacent electrode assemblies in the electrode stack 15 and seal the internal space. This internal space contains an electrolyte solution (not shown) containing, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The electrolyte solution is impregnated into, for example, the separators, positive electrodes, and negative electrodes that make up the electrode stack 15.

[0019] As shown in FIGS. 1 and 2, a plurality of liquid filling ports 30 are provided on one wall surface 16a constituting the seal member 16. A liquid filling port frame 32 surrounding each liquid filling port 30 is provided on the wall surface 16a. Each liquid filling port 30 communicates with the internal space of a different cell. An electrolyte solution is poured into the internal space of the electrode stack 15 through each liquid filling port 30.

[0020] In this embodiment, the 24 liquid inlets 30 are arranged in four regions A1 to A4 that are perpendicular to the stacking direction (Z direction) and aligned in a direction (Y direction) along the wall surface 16a. When viewed from the direction facing the wall surface 16a (X direction), the regions A1 to A4 are arranged in this order from right to left. Each of the regions A1 to A4 is of the same size and is an area where a pressure adjustment valve (not shown) is attached. Six liquid inlets 30 open in each of the regions A1 to A4.

[0021] Region A1 is divided into three rows along the Y direction, with two pouring ports 30 in each row arranged along the stacking direction (Z direction). Region A2 has six pouring ports 30 arranged one row below the six pouring ports 30 arranged in region A1 in the stacking direction. Region A3 has six pouring ports 30 arranged two rows below the six pouring ports 30 arranged in region A1 in the stacking direction. Region A4 has six pouring ports 30 arranged three rows below the six pouring ports 30 arranged in region A1 in the stacking direction. Thus, in this embodiment, as an example, the 24 pouring ports 30 are arranged point-symmetrically with respect to the center C of wall surface 16a when viewed from the direction facing wall surface 16a (X direction).

[0022] Here, the shape of the liquid pouring port 30 will be described.

[0023] FIG. 3 is a schematic plan view showing one liquid inlet 30 and liquid inlet frame 32, and an enlarged view showing a portion of an end of the liquid inlet 30. As shown in FIG. 3, the liquid inlet 30 has a wave-like shape when viewed from the liquid inlet direction (the X direction in FIG. 3), in which wide areas 30A and narrow areas 30B are alternately repeated. When no external force is applied from the outside (for example, when no external force is applied to the liquid inlet frame 32 from the outside), the liquid inlet 30 has a shape formed by walls 31Aa and 31Ab. In other words, the liquid inlet 30 has a shape in which the opposing walls 31Aa and 31Ab do not contact each other in the narrow areas 30B. The liquid inlet direction refers to the direction in which the electrolyte flows through the liquid inlet 30 when the electrolyte is poured into the internal space of the electrode stack 15 through the liquid inlet 30.

[0024] Here, a method for forming the liquid inlet 30 having a wavy shape in which wide wide areas 30A and narrow narrow areas 30B are alternately repeated, as shown in Fig. 3, will be described. Conventionally, a liquid inlet having a flat, slit-like cross-sectional shape has been obtained by forming the liquid inlet using a flat nest with flat front and back surfaces. In contrast, by forming the liquid inlet using a nest having a wavy cross-sectional shape in which wide wide areas and narrow narrow areas are alternately repeated, a battery having the liquid inlet 30 having a wavy cross-sectional shape in which wide wide areas 30A and narrow narrow areas 30B are alternately repeated, as shown in Fig. 3, can be obtained.

[0025] As shown in FIG. 3, the shape of the battery according to the embodiment of the present disclosure when viewed from the injection direction of the injection port is a wavy shape in which wide and narrow portions are alternately repeated, thereby suppressing a decrease in injection performance.

[0026] A conventional battery will now be described with reference to Figures 5 and 6. Figure 5 is a schematic perspective view showing one filler port and filler port frame in a conventional battery, and Figure 6 is a schematic cross-sectional view showing the state in which electrolyte is poured by pressing a packing against the filler port frame of the conventional battery.

[0027] The conventional battery shown in FIG. 5 has a liquid filling port 130 in a wall surface 16a of a sealing member 16. The liquid filling port 130 has a flat, slit-like shape. A liquid filling port frame 132 having a liquid filling port frame end 132a and a liquid filling port frame wall 132b is provided around the liquid filling port 130. To inject electrolyte 36 into the internal space of the electrode stack through the liquid filling port 130, a packing 34 serving as a liquid filling device is pressed against the liquid filling port frame 132 from the side of the liquid filling port frame end 132a, as shown in FIG. 6, causing the liquid filling port frame 132 to deform due to the pressure. The liquid filling port frame 132 is also deformed by the pressure applied to the electrolyte 36 during injection. Furthermore, the liquid filling port 130, which has a flat, slit-like shape when no external force is applied from the outside, is deformed by the pressure of the packing 34 and the like, resulting in the shape shown by liquid filling port 130X. Therefore, in the liquid injection port 130X to which pressure is applied, the opposing walls come into contact with each other and become blocked, which reduces the liquid injection efficiency.

[0028] In contrast, in the battery according to the embodiment of the present disclosure, the shape of the inlet, as viewed from the injection direction, is a wavy shape with alternating wide and narrow portions. Therefore, even if the inlet 30 is deformed by an external force, as shown in FIG. 3 , the inlet 30 remains shaped by the walls 31Ba and 31Bb. Therefore, the walls 31Ba and 31Bb contact each other at the narrow portion 30B, whereas the walls 31Ba and 31Bb do not contact each other at the wide portion 30A. In other words, the entire inlet 30 is not blocked, ensuring sufficient area for injection. This prevents deterioration of the inlet operability in the battery according to the embodiment of the present disclosure.

[0029] While FIGS. 2 and 3 show an embodiment in which one filler port 30 is provided within one filler port frame 32, the present disclosure is not limited to this embodiment. Two or more filler ports may be provided within one filler port frame. For example, a single filler port frame may include multiple filler ports arranged intermittently in a straight line. That is, a single filler port may include multiple filler ports arranged in a straight line and pillars arranged between the multiple filler ports to separate the filler ports. By providing pillars between the multiple filler ports, the filler ports are less likely to be deformed by external forces. Therefore, even when an external force is applied, blocking of the filler port when injecting electrolyte through the filler port is more likely to be suppressed, achieving better fillability.

[0030] 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. 4. The battery 2 shown in Fig. 4 has a configuration including a stack of multiple bipolar electrodes, a negative terminal electrode, and a positive terminal electrode. In Fig. 4, the "top surface" refers to the upper side of the figure, and the "bottom surface" refers to the lower side of the figure.

[0031] 4 is a schematic cross-sectional view of the battery 2. The battery 2 has a structure (multi-cell structure) in which a plurality of cells (e.g., 24 cells) are stacked. The battery 2 includes an electrode stack 15. One side of the module body 11 has a plurality of liquid filling ports (not shown in FIG. 4) that communicate with each of the plurality of (here, 24) internal spaces V.

[0032] The module body 11 includes an electrode stack 15 and a sealing member 16. The electrode stack 15 has a plurality of electrodes (bipolar electrodes 13, a positive terminal electrode 20, and a negative terminal electrode 21) stacked with separators 14 interposed therebetween. The sealing member 16 is provided so as to surround the electrode stack 15 when viewed in the stacking direction (Z direction) of the plurality of electrodes, and seals each of a plurality of internal spaces V formed between adjacent electrodes in the stacking direction.

[0033] The bipolar electrode 13 and separator 14 are, for example, rectangular in plan view. The separator 14 is disposed between adjacent bipolar electrodes 13 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 side) of the electrode plate 17, and a negative electrode 19 formed on a lower surface 17b (the other side) of the electrode plate 17.

[0034] The positive electrode 18 of one bipolar electrode 13 faces the negative electrode 19 of another bipolar electrode 13 adjacent to it in the stacking direction, with the separator 14 sandwiched between them. The negative electrode 19 of one bipolar electrode 13 faces the positive electrode 18 of the other bipolar electrode 13 adjacent to it in the stacking direction, with the separator 14 sandwiched between them.

[0035] A positive terminal electrode 20 is disposed in the bottom layer of the electrode stack 15. The positive terminal electrode 20 has an electrode plate 17 and a positive electrode 18 formed on the upper surface 17a of the electrode plate 17. A negative terminal electrode 21 is disposed in the top layer of the electrode stack 15. The negative terminal electrode 21 has an electrode plate 17 and a negative electrode 19 formed on the lower surface 17b of the electrode plate 17. The positive electrode 18 of the positive terminal electrode 20 faces the negative electrode 19 of the bipolar electrode 13 in the bottom layer, with the separator 14 in between. The negative electrode 19 of the negative terminal electrode 21 faces the positive electrode 18 of the bipolar electrode 13 in the top layer, with the separator 14 in between. The electrode plates 17 of the positive terminal electrode 20 and the negative terminal electrode 21 are connected to conductive plates (not shown) adjacent to each other in the stacking direction.

[0036] The electrode plate 17 may be, for example, a laminate of aluminum foil and copper foil. As an example, the electrode plate 17 is a rectangular metal laminate with aluminum foil on the positive electrode side and copper foil 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. For example, nickel hydroxide coated with cobalt (Co) oxide is used as the positive electrode active material. The negative electrode 19 is formed by applying a negative electrode active material to the other surface of the electrode plate 17. For example, a hydrogen storage alloy is used as the negative electrode active material. A peripheral portion 17c of the electrode plate 17 is an uncoated region where the positive electrode active material and the negative electrode active material are not applied.

[0037] The separator 14 is disposed between the positive electrode 18 and the negative electrode 19, and separates the positive electrode 18 from the negative electrode 19. When viewed in the stacking direction, the separator 14 is smaller than the electrode plate 17 and larger than the positive electrode 18 and the negative electrode 19. The separator 14 is formed, for example, in a sheet shape. The separator 14 is formed of a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), or a nonwoven or woven fabric made of PE, PP, methyl cellulose, or the like. The separator 14 may also be reinforced with a vinylidene fluoride resin compound or the like. The shape of the separator 14 is not particularly limited to a sheet shape, and may also be a bag shape.

[0038] The sealing member 16 holds the peripheral edge 17c of each electrode plate 17 on the side surface of the electrode stack 15. The sealing member 16 has a plurality of primary sealing portions 22 provided on the peripheral edge 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.

[0039] The primary seal 22 has a rectangular frame shape when viewed in the stacking direction and is continuously provided around the entire periphery of the peripheral edge 17c of the electrode plate 17. The primary seal 22 is, for example, hermetically welded to one side of the electrode plate 17. The primary seal 22 is welded, for example, by ultrasonic waves or heat. The primary seal 22 is a film having a predetermined thickness (length in the stacking direction). A portion of the inner side of the primary seal 22 is located between the peripheral edges 17c of adjacent electrode plates 17 in the stacking direction, and a portion of the outer side extends outward beyond the edge of the electrode plate 17. The outer portions of each of the multiple primary seals 22 are welded together. For example, a hot plate is applied to the outer portions of each of the multiple primary seals 22 to align and fix the ends together. However, the outer portions of each of the multiple primary seals 22 do not have to be fixed together by welding or the like. In this case, the secondary seal 23 may fit into the gap formed between the outer ends of each of the primary seals 22. The primary seal 22 is also provided on the edge of the lower surface 17b of the electrode plate 17 of the positive terminal electrode 20.

[0040] Between adjacent electrode plates 17 in the stacking direction, an internal space V is defined by the electrode plates 17, the positive electrode 18, the negative electrode 19, and the primary seal 22. Therefore, the electrode stack 15 has a plurality of internal spaces V. An electrolyte is poured into the internal spaces V, including the separators 14. The primary seal 22 seals the internal spaces V. Each cell of the battery 2 is composed of two electrode plates 17, a positive electrode 18, a negative electrode 19, a separator 14, and the primary seal 22, and has an internal space V.

[0041] The secondary seal 23 is provided on the outside of the electrode stack 15 and the primary seal 22, and constitutes the outer wall (casing) of the battery 2. When the secondary seal 23 is an integrally molded product, for example, it can be formed by resin injection molding. The secondary seal 23 extends over the entire length of the electrode stack 15 along the stacking direction. The secondary seal 23 is welded (bonded) to the outer surface of the primary seal 22 by, for example, heat during injection molding.

[0042] Furthermore, the sealing member 16 may be a member in which the primary seal portion 22 and the secondary seal portion 23 are integrally formed. For example, a pair of resin sheets may be provided for each electrode plate 17 so as to sandwich the end of the electrode plate 17 and extend beyond the end, and the primary seal portion 22 may be formed by welding the pair of resin sheets to each electrode plate 17. Furthermore, the resin sheets in the portions extending beyond the end of each electrode plate 17 may be welded to each other to form the secondary seal portion 23, thereby forming the sealing member 16 in which the primary seal portion 22 and the secondary seal portion 23 are integrally formed.

[0043] The primary seal portion 22 and the secondary seal portion 23 are formed of a resin such as polyethylene (PE), polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE).

[0044] Applications of the batteries according to embodiments of the present disclosure include, for example, power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicles (BEVs). The materials and shapes of the batteries according to embodiments of the present disclosure may be appropriately modified within the scope of the design intent for such applications. The shape of the battery may be any shape, such as a square or a rectangle. The battery may be a bipolar battery having a bipolar electrode body, or may be a monopolar battery. [Explanation of symbols]

[0045] 2 battery, 11 module body, 13 bipolar electrode, 14 separator, 15 electrode laminate, 16 sealing member, 16a wall surface, 17 electrode plate, 18 positive electrode, 19 negative electrode, 20 positive terminal electrode, 21 negative terminal electrode, 22 primary seal portion, 23 secondary seal portion, 30 filling port, 30A wide area portion, 30B narrow area portion, 31Aa, 31Ab, 31Ba, 31Bb wall, 32 filling port frame, 34 packing, 36 electrolyte

Claims

1. an electrode stack in which electrode bodies are stacked; a liquid injection port for injecting an electrolyte solution into an internal space of the electrode stack, the liquid injection port being provided on a side surface of the electrode stack in a stacking direction of the electrode stack; and The battery, wherein the injection port has a wave-like shape when viewed from the injection direction, with wide portions and narrow portions alternately repeated.

2. a liquid inlet frame arranged to surround the liquid inlet, 2. The battery according to claim 1, wherein the shape of the filling port as viewed from the filling direction is such that opposing walls at the narrow portion do not contact each other when no external force is applied to the filling port frame from the outside.

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