power storage module

Abstract

The utility model relates to a kind of battery modules, it has: electrode laminated body, laminated multiple electrodes are formed;Resin-made sealing component, along the periphery of the electrode laminated body Configuration, with the inside of the electrode laminated body is communicated through hole;Liquid injection frame, it is configured in the side of the sealing component, with the injection port of through hole communication;And sealing film, with the injection frame fusion, the injection port is sealed.The sealing film is fused in the opening end surface of the injection port of the injection frame, and fused in the inner surface of the injection port.Adopting the utility model, air-tightness can be inhibited in the structure of sealing injection frame by sealing film.

Description

Technical Field

[0001] This utility model relates to an energy storage module. Background Technology

[0002] Japanese Patent Application Publication No. 2024-088396 discloses an energy storage module having an electrode stack consisting of multiple stacked electrodes. A liquid injection frame is provided on the side of the electrode stack, and the liquid injection port of the liquid injection frame is sealed by a sealing membrane. In this structure, although the liquid injection port is sealed by fusing the sealing membrane to the liquid injection frame, since the sealing membrane is only fused to the open end face of the liquid injection port, the fusion area cannot be sufficiently obtained, which may result in poor airtightness. Utility Model Content

[0003] This invention was made in view of the above circumstances, and its purpose is to provide an energy storage module that can suppress poor airtightness in a structure in which the liquid injection frame is sealed by a sealing membrane.

[0004] The energy storage module of this utility model comprises: an electrode stack, formed by stacking multiple electrodes; a resin sealing member disposed along the periphery of the electrode stack and having a through hole communicating with the interior of the electrode stack; a liquid injection frame disposed on the side of the sealing member and having a liquid injection port communicating with the through hole; and a sealing membrane fused to the liquid injection frame to seal the liquid injection port. The sealing membrane is fused to the open end face of the liquid injection port of the liquid injection frame and to the inner surface of the liquid injection port.

[0005] In this invention, the sealing film can be fused to the inner surface of the injection port within its entire circumference.

[0006] By employing this invention, poor airtightness can be suppressed in the structure of the liquid injection frame sealed by a sealing membrane. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating the energy storage module in the implementation method.

[0008] Figure 2 This is a cross-sectional view showing a sealing structure that uses a sealing membrane to seal the injection port.

[0009] Figure 3 It is a cross-sectional view showing the sealed state of the welded part inside the injection port after it peels off when the internal pressure of the energy storage module rises.

[0010] Figure 4 This diagram illustrates the sealing process included in the manufacturing method of a battery storage module.

[0011] Figure 5 This diagram illustrates the process of welding the sealing membrane to the injection frame during the sealing process.

[0012] Figure 6 This is a cross-sectional view showing the structure of the thermal rod in the modified example.

[0013] Figure 7 This is a cross-sectional view showing the construction of the thermal rod in other variations.

[0014] Figure 8 This diagram illustrates a scenario where a sealing process is performed using a hot rod from another variation. Detailed Implementation

[0015] The following describes in detail the energy storage module and its manufacturing method in the embodiments of this utility model. Furthermore, this utility model is not limited to the embodiments described below.

[0016] Figure 1 This is a schematic diagram illustrating the energy storage module in the embodiment. The energy storage module 1 includes an electrode stack 2 formed by stacking multiple electrodes, a resin sealing member 3 that seals the electrode stack 2, an injection frame 4 including an injection port, and a sealing membrane 5 that seals the injection port.

[0017] Energy storage module 1 is a bipolar battery composed of stacked bipolar electrodes. Energy storage module 1 has a cuboid shape where the depth dimension is longer than the width dimension. For example... Figure 1 As shown, the X direction is the same as the depth direction of the energy storage module 1, and the Y direction is the same as the width direction of the energy storage module 1.

[0018] The energy storage module 1 has a structure in which multiple battery cells are stacked in the direction of bipolar electrode stacking. The bipolar electrodes are stacked in the Z direction. The Z direction is the same as the height direction of the energy storage module 1 and the same as the stacking direction of the electrode stack 2.

[0019] The electrode stack 2 has a structure comprising multiple bipolar electrodes, a positive terminal electrode, a negative terminal electrode, and multiple separators stacked together. The bipolar electrode comprises a current collector, a positive active material layer, and a negative active material layer. In the bipolar electrode, the positive active material layer is disposed on one side of the current collector, and the negative active material layer is disposed on the other side of the current collector. The positive active material layer is smaller in shape than the current collector. One side of the current collector includes an uncoated portion. This uncoated portion is the area where the positive active material layer is not disposed, located at the periphery of the current collector. The periphery of the current collector is the periphery of the electrode stack 2. The negative active material layer is smaller in shape than the current collector. The other side of the current collector includes an uncoated portion. This uncoated portion is the area where the negative active material layer is not disposed, located at the periphery of the current collector.

[0020] The positive terminal electrode has a positive current collector and a positive active material layer disposed on one side of the positive current collector. The negative terminal electrode has a negative current collector and a negative active material layer disposed on one side of the negative current collector. Between the positive and negative terminal electrodes, bipolar electrodes and separators are alternately stacked. In adjacent bipolar electrodes in the stacking direction, the positive active material layer of one bipolar electrode is stacked with the negative active material layer of the other bipolar electrode through the separator.

[0021] A battery cell comprises an electrode stack 2, a sealing member 3, and an electrolyte. Adjacent battery cells in the stacking direction share a bipolar electrode and are electrically connected in series via this bipolar electrode. The electrolyte is contained within an internal space defined by adjacent current collectors in the stacking direction and the sealing member 3 located between these current collectors. The electrolyte is also contained within an internal space defined by the bipolar electrodes, the positive terminal electrode, and the sealing member 3 located between them. Finally, the electrolyte is contained within an internal space defined by the bipolar electrodes, the negative terminal electrode, and the sealing member 3 located between them.

[0022] A sealing member 3 is formed in a frame that forms the outer frame of the energy storage module 1. The sealing member 3 is disposed along the periphery of the electrode laminate 2. The sealing member 3 is located at the periphery of the current collector, disposed in a manner that does not contact the positive electrode active material layer or the negative electrode active material layer. The sealing member 3 is made of multiple layers of resin. The sealing member 3 is made of polypropylene, polyethylene, polyphenylene sulfide fire-retardant material, polystyrene, ABS resin, AS resin, etc. The energy storage module 1 has a structure in which the periphery of the current collector is laminated with multiple layers of resin.

[0023] like Figure 2 As shown, the sealing member 3 has a through hole 31 communicating with the interior of the electrode stack 2. The through hole 31 is a hole for supplying electrolyte to the interior of the electrode stack 2, and is provided for each battery cell. The through hole 31 extends along the X direction and penetrates the sealing member 3, communicating with the internal space of the corresponding battery cell.

[0024] A through hole 31 corresponding to each battery cell is provided on the side 32 of the sealing member 3. The side 32 is a surface facing the X direction. The side surfaces of the sealing member 3 include two sides facing the X direction and two sides facing the Y direction. The sealing member 3 has four side surfaces.

[0025] The injection frame 4 is a resin component disposed on the side 32 of the sealing member 3. The injection frame 4 has an injection port 41 for supplying electrolyte to the interior of the electrode laminate 2. The injection port 41 extends along the X direction and communicates with the through hole 31 of the sealing member 3. The injection port 41 is provided for each through hole 31. The injection port 41 opens to one side facing the X direction. The injection frame 4 has an open end face 4a of the injection port 41 and an inner surface 4b of the injection port 41.

[0026] The opening end face 4a is one side face in the X direction. When viewed from one side in the X direction, the injection port 41 is open in a quadrilateral shape. The opening end face 4a is formed into a quadrilateral frame shape. The inner surface 4b includes two inner surfaces facing the Z direction and two inner surfaces facing the Y direction. The inner surface 4b includes four faces.

[0027] The sealing membrane 5 is a sealing component that seals the injection port 41. The sealing membrane 5 comprises a heat-flexible resin layer and a metal layer to prevent moisture inflow. The sealing membrane 5 is constructed by laminating the resin layer and the metal layer. The portion of the sealing membrane 5 that contacts the injection frame 4 is composed of the resin layer. The resin layer comprises a heat-flexible resin. The resin layer of the sealing membrane 5 is thermally fused to the injection frame 4.

[0028] The energy storage module 1 has a welded portion where a sealing membrane 5 is fused to a liquid filling frame 4. The welded portion includes a first welded portion formed by fusing the sealing membrane 5 to an open end face 4a and a second welded portion formed by fusing the sealing membrane 5 to an inner surface 4b.

[0029] The sealing membrane 5 includes a portion fused to the injection frame 4 and a portion that is not fused to the injection frame 4 but covers the injection port 41 (non-fused portion). The sealing membrane 5 is fused to the open end face 4a of the injection port 41 of the injection frame 4, and is fused to the inner surface 4b along the X direction from the open end face of the injection port 41 toward the inside of the injection port 41. In the second fused portion, the sealing membrane 5 is fused to the inner surface 4b over the entire circumference of the injection port 41. That is, in the fused portion 2, the sealing membrane 5 is fused to the four faces included by the inner surface 4b.

[0030] The weld area between the sealing membrane 5 and the liquid injection frame 4 is represented by the sum of the weld areas of the first weld and the second weld. Compared with existing sealing structures that seal the open end face, the weld area of ​​the energy storage module 1 is increased by the amount of the weld area of ​​the second weld. The increased weld area between the sealing membrane 5 and the liquid injection frame 4 improves airtightness. In the energy storage module 1, the increased weld area between the sealing membrane 5 and the liquid injection frame 4 prevents poor airtightness.

[0031] like Figure 3As shown, in the energy storage module 1, when the internal pressure of the electrode stack 2 rises, the fusion state between the sealing film 5 and the opening end face 4a is maintained, while the fusion state between the sealing film 5 and the inner surface 4b is released. In this case, although the amount of the second fusion portion is reduced, the amount of the first fusion portion is retained. Since the first fusion portion is the part where the opening end face 4a is fused with the sealing film 5, a fusion area equal to that in existing sealing structures where the opening end face is fused with the sealing material can be ensured. Moreover, since the non-fusion portion of the sealing film 5 is increased by an amount corresponding to the amount of peeling off the second fusion portion, this non-fusion portion can expand as the internal pressure rises, ensuring a larger internal space for the energy storage module 1. Thus, by increasing the internal space of the energy storage module 1 when the internal pressure of the energy storage module 1 rises, the rise in internal pressure of the energy storage module 1 can be suppressed, and poor sealing can be prevented.

[0032] The manufacturing method of the energy storage module 1 in the embodiment includes a liquid injection process, an initial charging process, a high-temperature aging process (high-temperature aging process), and a sealing process.

[0033] The electrolyte injection process is the process of injecting electrolyte into the interior of the electrode stack 2 through the electrolyte injection port 41. During the electrolyte injection process, electrolyte is supplied from the electrolyte injection port 41 to the through-hole 31, and the electrolyte is injected into the internal space of the battery cell through the through-hole 31. The initial charging process is the process of performing an initial charge after the electrolyte injection process. The high-temperature aging process is a known high-temperature aging process performed after the initial charging process. The sealing process is the process of sealing the electrolyte injection port 41 with a sealing membrane 5.

[0034] like Figure 4 , Figure 5 As shown, the sealing process involves using a heating rod 6 to thermally fuse the sealing membrane 5 and the injection frame 4, thereby sealing the injection port 41 with the sealing membrane 5. A heater 7 is installed inside the heating rod 6. The heating rod 6 receives heat from the heater 7, causing its temperature to rise. Figure 5 As shown, in the sealing process, the hot rod 6 is pressed onto the sealing membrane 5 and the liquid injection frame 4, so that the opening end face 4a and the sealing membrane 5 are thermally fused together, and the inner surface 4b and the sealing membrane 5 are thermally fused together.

[0035] The heating rod 6 has a flat portion 61 and a protruding portion 62. The flat portion 61 is the part where the sealing film 5 is pressed against the opening end face 4a to thermally fuse the sealing film 5 with the liquid injection frame 4. The flat portion 61 is formed as a plane. In the sealing process, the opening end face 4a and the sealing film 5 are thermally fused using the flat portion 61, and the inner surface 4b is thermally fused with the sealing film 5 using the protruding portion 62.

[0036] The protrusion 62 is the portion that protrudes from the flat portion 61. The protrusion 62 is the portion that presses the sealing film 5 against the inner surface 4b to fuse the sealing film 5 with the injection frame 4. The protrusion 62 is formed to match the opening shape of the injection port 41. For example, the protrusion 62 is formed to be slightly smaller than the opening shape of the injection port 41. When the opening of the injection port 41 is quadrilateral when viewed from the X direction, the protrusion 62 is formed to match the opening shape of the quadrilateral. Therefore, by inserting the protrusion 62 into the injection port 41 from one side in the X direction, the sealing film 5 can be sandwiched between the protrusion 62 and the inner surface 4b.

[0037] As explained above, according to the embodiment, the welding area between the sealing film 5 and the liquid injection frame 4 is large, thus improving the airtightness of the energy storage module 1. Furthermore, when the internal pressure of the energy storage module 1 rises, the second welding portion at the welding point where the sealing film 5 and the liquid injection frame 4 are welded together peels off while maintaining the first welding portion. This increases the internal space of the energy storage module 1 when the internal pressure of the energy storage module 1 rises, thereby reducing the internal pressure of the energy storage module 1.

[0038] Furthermore, the second welded portion where the sealing film 5 is welded to the inner surface 4b is not limited to a structure in which it is welded to the inner surface 4b along the entire circumference of the injection port 41, but can also be a structure in which it is welded to at least one of the four surfaces included in the inner surface 4b.

[0039] Furthermore, the shape of the heating rod 6 and the configuration of the heater 7 are not limited to... Figure 4 , Figure 5 Example structure. For example... Figure 6 As shown, the heating rod 6 may also have a trapezoidal protrusion 63. Additionally, as... Figure 7 , Figure 8 As shown, the heater 7 may also have a first heater 71 and a second heater 72 disposed inside the protrusion 63. Figure 8 As shown, when the sealing film 5 is melted during the sealing process, the temperature of the first heater 71 and the temperature of the second heater 72 can be adjusted independently. Therefore, the temperature of the heating rod 6 can be adjusted independently for the opening end face 4a and the inner surface 4b respectively.

Claims

1. A power storage module, characterized in that, have: An electrode stack is composed of multiple stacked electrodes. A resin-made sealing component is disposed along the periphery of the electrode stack and has a through hole communicating with the interior of the electrode stack. The injection frame is disposed on the side of the sealing component and has an injection port communicating with the through hole; and A sealing membrane is fused to the injection frame to seal the injection port. The sealing film is fused to the open end face of the injection port of the injection frame, and is also fused to the inner surface of the injection port.

2. The energy storage module according to claim 1, characterized in that, The sealing membrane is fused to the inner surface of the injection port over its entire circumference.

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