Energy storage device, energy storage module and mobile body

Abstract

When the internal pressure exceeds a certain level, the gas is released to the outside to prevent ignition. [Solution] This is an electricity storage device having an electrode unit, an exterior member that covers the electrode unit, and a terminal unit. The exterior member has a housing portion that houses the electrode unit, and a sealing strip portion that is connected to the outer edge of the housing portion and directly or indirectly bonds the first packaging material and the second packaging material. The sealing strip portion has a first sealing portion where the first packaging material and the second packaging material are bonded to the electrode unit, a second sealing portion where the first packaging material and the second packaging material are directly bonded, and a fastening portion that imparts adhesive strength to the first packaging material and the second packaging material. A weak sealing portion is formed in the sealing strip portion, which has weaker adhesive strength than other portions.

Description

[Technical Field]

[0001] The present invention relates to a power storage device, a power storage module including the power storage device, and a mobile body including the power storage module. [Background technology]

[0002] A conventional electricity storage device is disclosed in Patent Document 1. In this electricity storage device, an electricity storage element is enclosed in an exterior member. The electricity storage element has a positive electrode plate and a negative electrode plate arranged opposite each other with a separator interposed therebetween, and an electrolyte is disposed between the positive electrode plate and the negative electrode plate. The electricity storage device has a configuration in which the electricity storage element is housed inside an exterior member formed of a resin film including a metal layer or a barrier layer. The electricity storage element and electrolyte are covered with a resin film, and the outer edges are sealed, thereby sealing the electricity storage element in the exterior member.

[0003] Also, an electricity storage module is used in which a plurality of electricity storage devices having such a configuration are arranged side by side, and the electricity storage devices are connected in parallel or series and housed in a module, pack, or directly in a mobile body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3852110 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the storage capacity of electricity storage devices has been increasing, and as the storage capacity increases, the internal pressure acting on the exterior material due to gas generation during rapid charging of the electricity storage element tends to increase. Furthermore, thermal runaway may occur in the event of a battery malfunction such as an internal short circuit, and when thermal runaway occurs, the battery temperature may rise rapidly, potentially leading to smoke or fire.

[0006] The present invention aims to provide an energy storage module that, when the internal pressure and temperature rise due to repeated rapid charging and exceed a certain level, releases the internal gas to the outside from a predetermined location, thereby suppressing smoke and fire. [Means for solving the problem]

[0007] An exemplary power storage device of the present invention includes an elongated electrode unit in which positive and negative electrode plates are alternately stacked with an intermediate member interposed therebetween, an exterior member including first and second packaging materials that cover the electrode unit from both outer sides in the stacking direction of the electrode unit, and terminal portions electrically connected to the positive and negative electrode plates, respectively. The exterior member includes a housing portion that houses the electrode unit, and a sealing strip portion that is connected to at least a portion of the outer edge of the housing portion and directly or indirectly joins the first packaging material and the second packaging material to seal the housing portion. The sealing strip portion includes a fastening portion that applies a fastening force to the first packaging material and the second packaging material in the stacking direction by a fastening member that penetrates and fastens the first packaging material and the second packaging material, and a weak sealing portion in which the joining strength between the first packaging material and the second packaging material is weaker than that of other portions of the sealing strip portion. [Effects of the Invention]

[0008] According to the present invention, repeated rapid charging causes the internal pressure and temperature to rise, and when they reach a certain level or higher, the internal gas is released to the outside from a predetermined position, thereby preventing smoke and fire. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of the electricity storage device 1. FIG. [Figure 2] FIG. 2 is a cross-sectional view of the electricity storage device shown in FIG. 1 taken along line II-II. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the electricity storage device shown in FIG. 1 taken along line III-III. [Figure 4] FIG. 4 is a cross-sectional view showing a laminated structure of resin sheets. [Figure 5]FIG. 5 is an exploded perspective view of the electricity storage device. [Figure 6] FIG. 6 is a perspective view of the electricity storage module. [Figure 7] FIG. 7 is a cross-sectional view taken along plane VII of the electricity storage module shown in FIG. [Figure 8] FIG. 8 is a side view of the electric vehicle. [Figure 9] FIG. 9 is a plan view of the electric vehicle. [Figure 10] FIG. 10 is an enlarged view of a weakly sealed portion of the electricity accumulation device of the first modified example. [Figure 11] FIG. 11 is a front view of an electricity accumulation device according to a second modified example. [Figure 12] FIG. 12 is a front view of an electricity accumulation device according to a third modified example. [Figure 13] FIG. 13 is an enlarged front view of an electricity accumulation device according to a fourth modified example. [Figure 14] 14 is a cross-sectional view of the electricity storage device shown in FIG. 13 taken along line XIV-XIV. [Figure 15] FIG. 15 is a plan view of the terminal portion. [Figure 16] FIG. 16 is an enlarged cross-sectional view of a fastening portion of an electricity accumulation device according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an electricity storage device according to one embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment and can be modified as desired within the scope of the technical concept of the present invention.

[0011] 1 and 2, the vertical direction of the energy storage device 1 is defined as the Y direction, the horizontal direction as the X direction, and the thickness direction as the Z direction. Note that the Z direction is the front-to-rear direction of the energy storage device 1. Each direction is given for convenience to facilitate explanation, and does not indicate the direction in actual use.

[0012] <Electricity storage device 1> Fig. 1 is a front view of the electricity storage device 1. Fig. 2 is a cross-sectional view of the electricity storage device 1 shown in Fig. 1 taken along line II-II. Fig. 3 is an enlarged cross-sectional view of the electricity storage device 1 shown in Fig. 1 taken along line III-III.

[0013] As shown in Fig. 1, when viewed from the front, the electricity storage device 1 has a rectangular shape with the longitudinal direction in the X direction. As shown in Figs. 1, 2, and 3, the electricity storage device 1 has an exterior member 10, an electricity storage element 20, and a terminal portion 30. The electricity storage device 1 has a configuration in which an electricity storage element 20, such as a primary battery, a secondary battery, or an electric double layer capacitor (including EDLC), is housed in a housing portion 11 provided in the exterior member 10. Examples of the electricity storage device 1 include a lithium ion battery, a lithium ion polymer battery, a lithium ion all-solid-state battery, a lithium ion capacitor, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, and a polyvalent cation battery.

[0014] <Electricity storage element 20> As shown in FIG. 2 , in the energy storage device 1, the storage section 11 accommodates an energy storage element 20 together with an electrolyte. The energy storage element 20 has a positive electrode plate 21, a negative electrode plate 22, and a separator 23. The energy storage element 20 is formed by arranging the positive electrode plate 21 and the negative electrode plate 22 opposite each other with the insulating separator 23 interposed therebetween. The energy storage element 20 is formed by stacking sheet-like positive electrode plates 21, the separator 23, the negative electrode plate 22, and the separator 23 in this order in multiple stages in the Z direction. The energy storage device 1 accommodates the positive electrode plates 21 and the negative electrode plates 22 together with the electrolyte in the storage section 11 such that the stacking direction of the positive electrode plates 21 and the negative electrode plates 22 is the Z direction of the energy storage device 1.

[0015] In this embodiment, an electrolyte solution, which is a liquid electrolyte, is used as the electrolyte and is filled inside the housing portion 11. A solid electrolyte or a gel electrolyte may also be used as the electrolyte. The separator 23 is an example of an intermediate member disposed between the positive electrode plate 21 and the negative electrode plate 22. When a solid electrolyte is used as the electrolyte, the solid electrolyte is the intermediate member and there is no separator.

[0016] <Terminal part 30> The terminal portion 30 has a positive electrode terminal 31 and a negative electrode terminal 32. The positive electrode terminal 31 is connected to the positive electrode plate 21, and the negative electrode terminal 32 is connected to the negative electrode plate 22. The positive electrode terminal 31 and the negative electrode terminal 32 are conductive. As shown in FIGS. 1 and 2 , the positive electrode terminal 31 and the negative electrode terminal 32 pass through the first sealing portion 121 of the sealing strip portion 12 and protrude to the outside of the exterior member 10. In the energy storage device 1, the positive electrode terminal 31 and the negative electrode terminal 32 are input / output terminals for charging and discharging the energy storage element 20. In a front view of the energy storage device 1, the positive electrode terminal 31 and the negative electrode terminal 32 protrude outward from both ends in the X direction.

[0017] <Exterior member 10> The first packaging material 141 and the second packaging material 142 of the packaging member 10 are made of a resin sheet 40 having at least one insulating layer. FIG. 4 is a cross-sectional view showing the layered structure of the resin sheet 40. As shown in FIG. 4, the resin sheet 40 is formed by laminating at least a base material layer 41, a barrier layer 42, and a thermally adhesive resin layer 43 in this order. The thickness of the resin sheet 40 is desirably 50 μm or more in consideration of the strength of the packaging member 10, and is desirably 400 μm or less in consideration of reducing the weight of the electricity storage device 1. Note that the thicker the barrier layer 42, the higher the strength and thermal conductivity. Therefore, when the strength and thermal conductivity of the packaging member 10 are required even if the weight of the electricity storage device 1 increases, the thickness of the resin sheet 40 may be 1 mm to 2 mm or more.

[0018] The base material layer 41 has insulating properties and is formed from a resin film such as nylon, polyester, or polyethylene terephthalate. The thickness of the base material layer 41 is, for example, 10 μm or more and 75 μm or less. To improve heat resistance, it is more desirable to form the base material layer 41 from a uniaxially stretched film or a biaxially stretched film. The thicker the base material layer 41, the more disadvantageous its thermal conductivity in the Z direction. For example, if the barrier layer 42 can ensure sufficient thermal conductivity, the thickness of the base material layer 41 may be approximately 50 μm.

[0019] Furthermore, in order to improve pinhole resistance, insulation, etc., the base material layer 41 may be formed by laminating multiple resin films made of different materials. In this case, the multiple resin films are bonded together with a polyurethane-based, acrylic-based, or silicone-based adhesive, or an acid-modified resin, etc. In this embodiment, the resin sheet 40 is formed by laminating polyethylene terephthalate (thickness 12 μm) and nylon (thickness 15 μm) with an adhesive (thickness 4 μm).

[0020] The barrier layer 42 prevents the intrusion of water vapor, oxygen, light, and the like. For example, a metal foil such as aluminum, aluminum alloy, stainless steel, titanium, iron, or high-strength steel can be used as the barrier layer 42. The thickness of the barrier layer 42 is, for example, 10 μm or more and 500 μm or less. The base layer 41 and the barrier layer 42 are bonded together with a polyurethane-based, acrylic-based, or silicone-based adhesive, or an acid-modified resin (not shown), or the like. In the resin sheet 40 of this embodiment, the barrier layer 42 is formed of an aluminum foil having a thickness of 40 μm.

[0021] The thermal adhesive resin layer 43 may be any resin having thermal adhesive properties, and is formed from a thermal adhesive resin such as polypropylene, acid-modified polypropylene, low-density polyethylene, linear low-density polyethylene, etc. The thermal adhesive resin layer 43 may be formed by laminating multiple resins of different materials. The thickness of the thermal adhesive resin layer 43 is, for example, 10 μm or more and 100 μm or less. The thermal adhesive resin layer 43 is formed by extrusion onto the barrier layer 42. A film forming the thermal adhesive resin layer 43 may be bonded onto the barrier layer 42 via an adhesive. The thickness of the thermal adhesive resin layer 43 may be 100 μm or more and 500 μm or less depending on the size of the energy storage element 20 to be accommodated in the accommodation section 11 and the weight of the energy storage element 20 and the electrolyte.

[0022] In the resin sheet 40 of this embodiment, the thermal adhesive resin layer 43 is formed by sequentially extruding acid-modified polypropylene (thickness: 40 μm) and polypropylene (thickness: 40 μm) onto the barrier layer 42. In the second sealing portion 122 of the sealing strip 12, the thermal adhesive resin layer 43 of the first packaging material 141 and the thermal adhesive resin layer 43 of the second packaging material 142 are brought into contact with each other and bonded by heat sealing by applying heat and pressure.

[0023] FIG. 5 is an exploded perspective view of the energy storage device 1. The exterior member 10 includes a first packaging material 141 and a second packaging material 142 that are integrally formed and continuous in the Y direction. The first packaging material 141 has a storage section 11 and a flange section 15. The first packaging material 141 and the second packaging material 142 are formed from resin sheets. The first packaging material 141 is formed, for example, by cold forming the storage section 11 into the flange section 15 to a predetermined depth. The storage section 11 has a substantially rectangular opening 11a on one side, and stores the energy storage element 20 therein. The flange section 15 protrudes from both short sides and one long side of the opening 11a toward the outer periphery. The second packaging material 142 is formed in a rectangular sheet shape. The second packaging material 142 is, for example, thermally bonded to the flange section 15 to form the sealing strip section 12. The second packaging material 142 also forms a lid section 16 that covers the opening 11a.

[0024] <Sealing belt portion 12> Next, the details of the sealing strip 12 will be described. The sealing strip 12 has two first sealing portions 121, a second sealing portion 122, and a fastening portion 123. When viewed from the front, the sealing strip 12 is strip-shaped and configured to connect to one of the long sides and both of the short sides of the storage portion 11. In the sealing strip 12, the first packaging material 141 and the second packaging material 142 are in close contact. Here, "close contact" refers to contact in a state in which gas generated by volatilization of the electrolyte sealed in the storage portion 11 and gas generated by rapid charging, etc., do not leak to the outside, and in which water vapor from the outside is blocked.

[0025] In the sealing strip 12, the first sealing portion 121 is a portion that overlaps the positive electrode terminal 31 or the negative electrode terminal 32 in the front and rear. The second sealing portion 122 is a portion of the sealing strip 12 other than the first sealing portion 121.

[0026] That is, in a front view, the portion of the sealing strip 12 that connects to both short sides of the housing section 11 and overlaps the positive electrode terminal 31 or the negative electrode terminal 32 in the front-to-rear direction is the first sealing portion 121. The entire portion of the sealing strip 12 that connects to one of the long sides of the housing section 11 and the portion that connects to the short sides other than the first sealing portion 121 are the second sealing portion 122.

[0027] In the first sealing portion 121, the positive electrode terminal 31 and the negative electrode terminal 32 of the terminal portion 30 are sandwiched between the flange portion 15 and the lid portion 16 via the thermally adhesive tab film 50. In this state, the flange portion 15 and the lid portion 16 are heated and pressurized. This indirectly melts and bonds the first packaging material 141 and the second packaging material 142. As a result, the sealing performance around the first sealing portion 121 is improved.

[0028] As a result, the first packaging material 141 and the second packaging material 142 in the first sealing portion 121 are in close contact with the positive electrode terminal 31 and the negative electrode terminal 32 of the terminal portion 30 .

[0029] Furthermore, the thermal adhesive resin layers 43 of the first packaging material 141 and the second packaging material 142 are in direct contact with each other in the second sealing portion 122. In this state, the first packaging material 141 and the second packaging material 142 are thermally bonded by applying heat and pressure to each other. That is, the first packaging material 141 and the second packaging material 142 are directly melted and bonded to each other in the second sealing portion 122.

[0030] In addition, the portion of the second sealing portion 122 adjacent to the long side of the housing portion 11 may be referred to as a long side portion 1221 , and the portion adjacent to the short side of the housing portion 11 may be referred to as a short side portion 1222 .

[0031] In addition, in the sealing belt portion 12, the fastening portion 123 is formed in the second sealing portion 122. The fastening portion 123 is formed by sewing together the first packaging material 141 and the second packaging material 142 with a wire 124 that has a higher heat resistance temperature than the resin sheet 40. The wire 124 is an example of a fastening member. Examples of the wire 124 include thin stainless steel wires, thin tungsten wires, and thin aramid fiber wires. The wire 124 is not limited to these, and any wire that has a higher heat resistance temperature than the resin sheet 40 or is flame-retardant can be used as the wire 124. The fastening portion 123 is not formed in the weak sealing portion 13, which will be described later. As shown in FIG. 1 and other figures, the fastening portion 123 sews together the first packaging material 141 and the second packaging material 142, including the tab film 50, but this is not limiting. For example, the tab film 50 may not be fastened by the fastening portion 123.

[0032] When the energy storage device 1 is repeatedly charged and discharged, particularly during rapid charging, the electrolyte contained in the storage section 11 heats up, accelerating decomposition and generating gas. The generated gas increases the pressure inside the storage section 11, and a force acts on the sealing strip 12 to separate the first packaging material 141 from the second packaging material 142. The force that separates the first packaging material 141 from the second packaging material 142 is a force corresponding to the amount and rate of gas generation, or expansion and contraction due to charging and discharging of the battery itself. Due to the shape characteristics of the sealing strip 12, the force that separates the first packaging material 141 from the second packaging material 142 tends to concentrate in the center in the X direction of the portion adjacent to the long side of the storage section 11. The fastening portion 123 formed in the second sealing section 122 counters the force that separates the first packaging material 141 from the second packaging material 142 with the fastening force of the fastening portion 123, making separation less likely.

[0033] 1, 2, and 3, the width from the inside to the outside of the first sealing portion 121 of the sealing strip 12 is defined as width W1, and the width from the inside to the outside of the second sealing portion 122 is defined as width W2. In this case, width W1 is larger than width W2. That is, width W1 of the first sealing portion 121 is larger than width W2 of the second sealing portion 122. As a result, the fastening strength of the first sealing portion 121 is higher than the fastening strength of the second sealing portion 122. Therefore, even if a force acts on the first sealing portion 121 to peel the first packaging material 141 and the second packaging material 142, peeling is unlikely to occur at the first sealing portion 121. Note that even if width W1 is narrow and the fastening strength is weak, an external auxiliary mechanism may be provided.

[0034] As described above, in the exterior member 10 of the electricity storage device 1, the width W1 is increased in the first sealing portion 121 to increase the area that is thermally bonded, thereby increasing the fastening strength and suppressing peeling between the first packaging material 141 and the second packaging material 142. Furthermore, in the second sealing portion 122, the fastening force of the fastening portion 123 counters the force that would peel the first packaging material 141 and the second packaging material 142, thereby suppressing peeling between the first packaging material 141 and the second packaging material 142.

[0035] Due to the shape characteristics of the sealing strip 12, the force for peeling the first packaging material 141 and the second packaging material 142 tends to concentrate at the center in the X direction of the portion adjacent to the long side of the containing section 11. In other words, the force for peeling the first packaging material 141 and the second packaging material 142 concentrates at the center of the long side portion 1221 of the second sealing portion 122.

[0036] In the power storage device 1, a weak sealing portion 13 is formed in the center in the X direction of a long side portion 1221 of the second sealing portion 122. As shown in FIG. 1 etc., no fastening portion 123 is formed in the weak sealing portion 13. The bonding strength of the weak sealing portion 13 configured in this manner is smaller than the bonding strength of other portions of the first sealing portion 121 and the second sealing portion 122.

[0037] When the internal pressure of the storage unit 11 of the electricity storage device 1 increases, the first packaging material 141 and the second packaging material 142 peel off at the weak sealing portion 13 in the sealing band 12 before the other portions. In other words, the weak sealing portion 13 is opened at a lower internal pressure than the other portions. As a result, a leak portion is formed in the weak sealing portion 13 to release gas inside the storage unit 11. The formation of the leak portion allows gas and electrolyte generated inside the storage unit 11 to be discharged to the outside. In other words, in the electricity storage device 1, gas generated by repeated rapid charging can be discharged to the outside when the internal pressure of the storage unit 11 reaches a certain pressure. Then, by providing the weak sealing portion 13 with a weaker sealing force than the other portions, the gas can be discharged from a predetermined position.

[0038] In the electricity storage device 1, smoke and fire occur when the following three conditions occur simultaneously: (1) gas generation due to accelerated decomposition of the electrolyte caused by high temperature, (2) spark generation between the positive electrode plate 21 and the negative electrode plate 22, and (3) oxygen generation from the positive electrode plate 21. In other words, smoke and fire can be suppressed by preventing these three conditions from occurring simultaneously. Therefore, in the electricity storage device 1 of this embodiment, when the internal pressure and temperature of the storage section 11 reach a certain level or higher, the weak sealing section 13 is opened and the gas inside the storage section 11 is discharged to the outside before the above-mentioned three conditions occur simultaneously. This suppresses smoke and fire from the electricity storage device 1.

[0039] Furthermore, when the gas inside the housing portion 11 of the exterior member 10 is discharged, the electrolyte is also discharged along with the gas. When the electrolyte is discharged, the chemical reaction between the positive electrode plate 21 and the negative electrode plate 22 is suppressed, the voltage between the positive electrode plate 21 and the negative electrode plate 22 decreases, and sparks between the positive electrode plate 21 and the negative electrode plate 22 are suppressed. For this reason, by discharging the gas accumulated inside the housing portion 11 at an early stage, it is possible to suppress smoke generation and fire from the electricity storage device 1.

[0040] As described above, the force for peeling the first packaging material 141 and the second packaging material 142 is concentrated in the center of the long side 1221 of the housing section 11 of the second sealing section 122, and so the weak sealed section 13 is formed in the center of the long side 1221. However, depending on the shape and installation state of the electricity storage device 1, the force may be concentrated in other locations. In such a configuration, the weak sealed section 13 may be provided in a portion other than the center of the long side 1221 of the second sealing section 122. In this case, the weak sealed section 13 in the center of the long side 1221 may be eliminated and a weak sealed section 13 may be formed in another location, or the weak sealed section 13 in the center may be left and a weak sealed section 13 may be added in a new portion.

[0041] In addition, in the power storage module 100 described below, the gas discharge position may be predetermined. In such a case, the weak sealing portion 13 may be formed at a position where the gas can be discharged to the required gas discharge position of the second sealing portion 122.

[0042] With this configuration, when repeated rapid charging of the electricity storage device 1 causes the electrolyte to decompose, generating gas, and the internal pressure to rise to a certain value, the gas can be discharged to the outside before the three conditions for ignition described above come together, thereby suppressing smoke and fire.

[0043] As described above, a so-called single-cup container in which the storage section 11 is formed as a recess in the first packaging material 141 is used as the exterior member 10 of the electricity storage device 1, but the present invention is not limited to this. For example, the exterior member 10 may be a double-cup container in which recesses are formed in both the first packaging material 141 and the second packaging material 142 and the openings are butted together. Alternatively, the exterior member 10 may be a four-sided sealed container in which a lid 16 made of the second packaging material 142 is sealed to flanges 15 extending outward from four sides of the opening 11a of the storage section 11. Furthermore, the first packaging material 141 and the second packaging material 142 may each be formed from separate sheets.

[0044] Furthermore, in the electricity storage device 1 of this embodiment, one of the long sides of the rectangular shape in a plan view is a folded portion between the first packaging material 141 and the second packaging material 142, the positive electrode terminal 31 is arranged on one short side, and the negative electrode terminal 32 is arranged on the other short side, and the weak sealing portion 13 is formed in the sealing band portion 12 provided on the long side. However, this configuration is not limited to this, and, for example, a configuration in which the positive electrode terminal 31 and the negative electrode terminal 32 are arranged on one short side may also be used. Furthermore, for example, a weak sealing portion 13 having a configuration similar to the weak sealing portion 13 may be formed in the sealing band portion 12 provided on at least one of the short sides. In this case, the weak sealing portion 13 formed in the sealing band portion 12 provided on the long side may be formed or may be omitted.

[0045] At least one of the positive electrode terminal 31 and the negative electrode terminal 32 may be disposed on the long side opposite the folded portion between the first packaging material 141 and the second packaging material 142, or both may be disposed on the long side. In this case, at least one weakly sealed portion 13 may be formed in the sealing strip 12 provided on at least one of the short sides, or at least one weakly sealed portion 13 may be formed in the sealing strip 12 provided on the long side.

[0046] Furthermore, when the electricity storage device 1A is a four-sided sealed type, the positive electrode terminal 31 may be arranged on the sealing band 12 provided on the short side or on the long side. The negative electrode terminal 32 may be arranged on the sealing band 12 provided on the short side or on the long side. In this case, at least one weakly sealed portion 13 may be formed in the sealing band 12 provided on at least one of the long sides, and at least one weakly sealed portion 13 may be formed in the sealing band 12 provided on at least one of the short sides.

[0047] <Electricity storage module 100> The details of the energy storage module 100 will be described below with reference to the drawings. Fig. 6 is a perspective view of the energy storage module 100. Fig. 7 is a cross-sectional view of the energy storage module 100 shown in Fig. 6 taken along plane VII. The energy storage module 100 is configured by housing a plurality of energy storage devices 1 in a case 200. Note that in the energy storage module 100 shown in Fig. 6, part of a body 201 is not shown to facilitate understanding.

[0048] As shown in FIG. 6, in the energy storage module 100, ten energy storage devices 1 are arranged inside the case 200; however, the actual number of devices arranged is not limited to ten, and the number and connection method of the energy storage devices 1 arranged in the energy storage module 100 may be changed depending on the required electric capacity, output voltage, etc. When the energy storage devices 1 are connected in parallel, the positive electrode terminals 31 and the negative electrode terminals 32 of adjacent energy storage devices 1 are arranged adjacent to each other. When the energy storage devices are connected in series, the positive electrode terminals 31 and the negative electrode terminals 32 of adjacent energy storage devices 1 are arranged adjacent to each other in the case 200. The energy storage devices 1 are assembled with the long side 1221 of the second sealing portion 122 of the sealing strip 12 arranged downward (see FIG. 7).

[0049] Case 200 has a body portion 201 and a closing portion 202. Body portion 201 is formed in a cylindrical shape with both axial ends open. Closing portions 202 close both axial ends of body portion 201. By attaching closing portions 202 to body portion 201, case 200 is sealed to prevent moisture from entering from the outside.

[0050] The case 200 is formed of an insulating material such as resin. To increase the strength of the case 200, a metal such as an aluminum alloy or stainless steel may be used. In this case, an insulating treatment is applied to the inner surface that comes into contact with the electricity storage device 1 and the portion that may come into contact with the electrode terminals.

[0051] The positive electrode terminal 31 and the negative electrode terminal 32 of each power storage device 1 are connected to a bus bar (not shown). Lead-out terminals (not shown) are connected to the bus bar and are drawn out to the outside of the case 200. The lead-out terminals are external connection terminals connected to external devices such as a charging device and a load.

[0052] The case 200 may be provided with an auxiliary mechanism (not shown) for increasing the fastening strength of the first sealing portion 121, and may be provided with a pressing member (not shown) for suppressing movement of the energy storage device 1 inside the case 200.

[0053] 7, a plurality of slits 204 are formed in the bottom plate 203 of the case 200. The number of slits 204 is the same as the number of the electricity storage devices 1. When the electricity storage devices 1 are attached to the case 200, the long side portions 1221 of the second sealing portion 122 of the sealing strip 12 of the electricity storage devices 1 are inserted into the slits 204.

[0054] The slits 204 penetrate the bottom plate portion 203 in the thickness direction. Therefore, in the electricity storage device 1, when the internal pressure of the accommodation portion 11 increases, the weak sealing portion 13 is opened, and gas is discharged from the weak sealing portion 13, the gas can be discharged to the outside of the case 200. By configuring the case 200 to discharge flammable gas to the outside in this way, it is possible to prevent the electricity storage device inside the case 200 from emitting smoke or catching fire.

[0055] <Electric vehicle 300> Fig. 8 is a side view of electric vehicle 300. Fig. 9 is a plan view of electric vehicle 300. Electric vehicle 300 is equipped with drive motor 302 as a power source for driving wheels 301. Under the floor of the vehicle body (main body of the moving body) of electric vehicle 300, a power storage pack 400 is installed as a drive source for supplying power to drive motor 302.

[0056] The electricity storage pack 400 has a configuration in which a plurality of electricity storage modules 100 are arranged side by side on an exterior member such as a frame (not shown). The electricity storage pack 400 can obtain a required electricity storage capacity and output a required output voltage by connecting the electricity storage modules 100 arranged on the exterior member such as a frame in series and parallel.

[0057] 9, in the electricity storage pack 400, the electricity storage modules 100 are arranged in a state where the Y direction is the height direction (gravity direction) of the electric vehicle 300, the Z direction is the front-rear direction of the electric vehicle 300, and the X direction is the left-right direction of the electric vehicle 300. In other words, in the electricity storage pack 400, the electricity storage modules 100 with the Y direction as the height direction are aligned in the X and Z directions.

[0058] The power storage module 100 is arranged so that the slits 204 open to the outside from the underside of the electric vehicle 300. By arranging the power storage module 100 in this manner, gas discharged from the weak sealing portion 13 of the power storage device 1 is discharged to the outside of the electric vehicle 300. This suppresses smoke and fire from the electric vehicle 300. Note that as long as the gas discharged from the slits 204 can be discharged to the outside of the electric vehicle 300, the slits 204 do not need to be directly exposed to the outside.

[0059] When the electric vehicle 300 is a sedan or compact car type with a low overall height, the power storage pack 400 uses a configuration in which the power storage modules 100 are arranged in a single stage in the height direction. When the electric vehicle 300 is an SUV or minivan type with a high overall height, the power storage modules 100 are arranged in a multi-stage configuration in the height direction of the vehicle. In this way, it is possible to provide a power storage pack 400 with an output voltage and power storage capacity according to the weight and size of the vehicle.

[0060] The power storage module 100 may also be arranged on the electric vehicle 300 so that the X direction, which intersects with the Z direction in which the power storage devices 1 are arranged, is the traveling direction. In this way, even when the power storage module 100 is arranged on the electric vehicle 300, the same effects as those described above can be obtained.

[0061] Furthermore, the power storage devices 1 may be directly arranged side by side under the floor (chassis) of the electric vehicle 300 to form a power storage unit with the same output voltage and power storage capacity as the power storage pack 400. In this way, exterior members such as a frame of the power storage pack 400 can be omitted, thereby enabling weight reduction. When the underfloor (chassis) of the electric vehicle 300 is configured in this way, the case 200 can also be omitted, enabling further weight reduction.

[0062] Furthermore, the portion for releasing gas to the outside (here, slit 204) is not limited to the bottom of electric vehicle 300, and may be determined according to the location of power storage module 100 on electric vehicle 300.

[0063] In addition to BEVs (Battery Electric Vehicles) and PHEVs (Plug-in Hybrid Electric Vehicles), examples of mobile objects on which the above-described power storage pack 400 is mounted include HEVs (Hybrid Electric Vehicles) and micro hybrid automobiles with 48V power supplies.

[0064] The above-described power storage module or power storage pack may be mounted on other moving objects. Examples of moving objects that may be mounted with a power storage module or power storage pack include bipedal robots, trains, airplanes, helicopters, drones, flying cars, agricultural machinery, and construction machinery. Note that if the required output voltage and power storage capacity are sufficient, the power storage module 100 may be configured to be used alone.

[0065] The power storage module or power storage pack may also be used for purposes other than as a driving source for a mobile object, such as an energy storage system, a battery energy storage system, or a fixed power source for an uninterruptible power supply.

[0066] <First Modification> 10, fastening portions 123 may also be formed in the weak sealing portion 131. In this case, if the fastening portions 123 in the second sealing portion 122 are formed at a pitch P1, the fastening portions 123 in the weak sealing portion 131 are formed at a pitch P2. The pitch P2 is larger than the pitch P1. By forming them in this manner, the bonding strength between the first packaging material 141 and the second packaging material 142 in the weak sealing portion 131 is weaker than in other parts of the second sealing portion 122. With this configuration, the weak sealing portion 131 is easily peeled off, and the weak sealing portion 131 is opened due to an increase in the internal pressure of the storage portion 11, allowing the internal gas to be discharged before smoke or fire occurs.

[0067] <Second Modification> 11, the weak sealing portion 132 may be formed in the first sealing portion 121. In this case, the width W3 of the weak sealing portion 132 extending from the accommodation portion 11 to the outside is narrower than the width W1 of the first sealing portion 121. By forming the weak sealing portion 132 in this manner, the weak sealing portion 132 peels off when the pressure inside the accommodation portion 11 reaches a certain pressure or higher. Gas inside the accommodation portion 11 is discharged to the outside through the peeled weak sealing portion 132. Note that sparks generated at the electrodes may ignite the gas. Therefore, when the weak sealing portion 132 is formed in the first sealing portion 121, it is preferably formed in the first sealing portion 121 where the negative electrode terminal 32 is disposed. A gas absorbing portion made of a gas-absorbing material may be disposed outside the weak sealing portion 131.

[0068] <Third Modification> An electricity storage device 1A of a third modified example will be described with reference to the drawings. Fig. 12 is a front view of the electricity storage device 1A of the third modified example. In the electricity storage device 1A shown in Fig. 12, the shape of the exterior member 10A, the electricity storage elements 20A, and the positive electrode terminal 31A and negative electrode terminal 32A of the terminal portion 30A are different from those of the exterior member 10, the electricity storage elements 20, and the positive electrode terminal 31 and negative electrode terminal 32 of the terminal portion 30. In all other respects, the electricity storage device 1A has the same configuration as the electricity storage device 1. Therefore, parts of the electricity storage device 1A that are substantially the same as those of the electricity storage device 1 are denoted by the same reference numerals, and detailed description of the same parts will be omitted.

[0069] 12, in a front view, the accommodation section 11 of the exterior member 10A of the power storage device 1A has a rectangular shape with the longitudinal direction in the Y direction. Two first sealing portions 121 are formed on both ends in the X direction of a portion of the sealing strip 12A that connects to one end side of the accommodation section 11 in the Y direction. A positive electrode terminal 31A is disposed in one of the two first sealing portions 121A, and a negative electrode terminal 32A is disposed in the other. The portion of the sealing strip 12A other than the first sealing portion 121A is a second sealing portion 122A.

[0070] In the electricity storage device 1A, the width of the first sealing portion 121A from the accommodation portion 11 toward the outside is larger than the width of the other portions of the sealing strip portion 12. Therefore, in the first sealing portion 121A, the adhesive strength between the positive electrode terminal 31A or the negative electrode terminal 32A and the first packaging material 141 and the second packaging material 142 is high. In addition, a weak sealing portion 133 is formed in a part of the second sealing portion 122A. And, a fastening portion 123 is formed in the portion of the second sealing portion 122A other than the weak sealing portion 133.

[0071] As a result, when the energy storage device 1A is repeatedly charged and discharged and the pressure inside the storage section 11 increases, the first packaging material 141 and the second packaging material 142 are peeled off at the weak sealing section 133, and the internal gas is released before smoke or fire occurs.

[0072] In addition, in the power storage device 1A of this modification, one of the short sides of the rectangular shape in a plan view is a folded portion between the first packaging material 141 and the second packaging material 142, the positive electrode terminal 31A and the negative electrode terminal 32A are arranged on one short side, and the weak sealing portion 13 is formed in the sealing strip portion 12 provided on one long side. However, this configuration is not limited to this. For example, at least one of the positive electrode terminal 31A and the negative electrode terminal 32A may be arranged on the long side, or both may be arranged on the long side. In this case, the positive electrode terminal 31A may be arranged on one long side and the negative electrode terminal 32A may be arranged on the other long side, or the positive electrode terminal 32A and the negative electrode terminal 32A may be arranged on one long side.

[0073] In this case, at least one weak sealed portion 133 may be formed in the sealing band portion 12 provided on one of the long sides, or at least one may be formed in each of the sealing band portions 12 provided on both long sides. Also, at least one weak sealed portion 133 may be formed in the sealing band portion 12 provided on the short side, and at least one weak sealed portion 133 may be formed on one of the long sides. Furthermore, at least one weak sealed portion 133 may be formed in the sealing band portion 12 provided on the short side, and at least one weak sealed portion 133 may be formed on each of the long sides.

[0074] <Fourth Modification> Further examples of electricity storage devices will be described with reference to the drawings. FIG. 13 is an enlarged front view of an electricity storage device 1B according to a fourth modified example. FIG. 14 is a cross-sectional view of the electricity storage device 1B shown in FIG. 13 taken along line XIV-XIV. FIG. 13 shows an enlarged view of the vicinity of the positive electrode terminal 31B of the terminal portion 30B of the electricity storage device 1B. In the electricity storage device 1B, the shape of the positive electrode terminal 31B of the exterior member 10B is different from that of the positive electrode terminal 31, and the configuration of the fastening portion 125 of the sealing band portion 12B is different from that of the fastening portion 123 of the sealing band portion 12. In other respects, the electricity storage device 1B has the same configuration as the electricity storage device 1. The same parts of the electricity storage device 1B as those of the electricity storage device 1 are denoted by the same reference numerals, and detailed description of the same parts will be omitted. The negative electrode terminal (not shown) also has the same configuration.

[0075] 13 and 14, in the power storage device 1B, a positive electrode terminal 31B is formed with a plurality of through holes 311 penetrating in the Z direction. The through holes 311 are formed side by side in the Y direction. In the first sealing portion 121B of the power storage device 1B, the wire 124 of the fastening portion 125 penetrates the first packaging material 141, the through holes 311, and the second packaging material 142. More specifically, the wire 124 is inserted into the through holes 311, and the first packaging material 141 and the second packaging material 142 are sewn to the positive electrode terminal 31B in the first sealing portion 121B to form the fastening portion 125.

[0076] This configuration suppresses peeling between the first packaging material 141 and the second packaging material 142 in the first sealing portion 121. In the electricity storage device 1B, the fastening portion 125 is formed over the entire length of the sealing strip portion 12B. This configuration allows the entire fastening portion 125 to be formed from a single wire, making it less likely that a portion of the fastening portion 125 will be weaker than the other portions. This increases the fastening force of the fastening portion 125. The fastening portion 125 may also be partially discontinuous. For example, the fastening portion 125 may be formed by dividing it into a portion located at both ends of the sealing strip portion 12B in the X direction and a portion located at one end in the Y direction.

[0077] 15, the portion of the positive electrode terminal 31B where the fastening portion 125 is formed may be a mesh portion 312 having a mesh shape. With this configuration, the fastening portion 125 can be formed in the first sealing portion 121B using a sewing machine or the like. This makes it possible to easily form the fastening portion 125 in the first sealing portion 121B. The opening area ratio of the mesh portion 312 is preferably set to a ratio that allows the positive electrode terminal 31B to have a certain level of rigidity or more, while also allowing the wire 124 to be easily sewn. The negative electrode terminal may have a similar configuration.

[0078] <Fifth Modification> Still another example of an electricity storage device will be described with reference to the drawings. Fig. 16 is an enlarged cross-sectional view of a fastening portion 126 of an electricity storage device 1C according to a fifth modified example. The configuration of the fastening portion 126 in the electricity storage device 1C is different from the fastening portion 123 of the electricity storage device 1. Other than this, the electricity storage device 1C has the same configuration as the electricity storage device 1. The same parts of the electricity storage device 1C as those of the electricity storage device 1 are denoted by the same reference numerals, and detailed description of the same parts will be omitted.

[0079] As shown in FIG. 16, the fastening portion 126 of the electricity storage device 1C uses staples 127. The first packaging material 141 and the second packaging material 142 are fastened together over the entire length of the second sealing portion 122. The staples 127 are an example of a fastening member. By configuring the fastening portion 126 using the staples 127 in this way, it is easier to manufacture than a fastening portion configured by sewing together wire. The staple material can be a metal, but the same material as the wire 124 can be selected.

[0080] The present invention is not limited to the above-described configuration, and various modifications are possible. Configurations obtained by appropriately combining the technical means disclosed in different configurations are also included in the technical scope of the present invention.

[0081] <Summary> The electricity storage module of the present invention has the following configuration.

[0082] (1) a long electrode portion in which positive electrode plates and negative electrode plates are alternately stacked with intermediate members interposed therebetween; an exterior member including a first packaging material and a second packaging material that cover the electrode portion from both outer sides in the stacking direction of the electrode portion; a terminal portion electrically connected to each of the positive electrode plate and the negative electrode plate, The exterior member is a housing portion that houses the electrode portion; a sealing belt portion connected to at least a part of the outer edge of the storage portion to directly or indirectly join the first packaging material and the second packaging material to seal the storage portion; The sealing strip is a fastening portion that applies a fastening force in a stacking direction to the first packaging material and the second packaging material by a fastening member that penetrates and fastens the first packaging material and the second packaging material; a weakly sealed portion in which the bonding strength between the first packaging material and the second packaging material is weaker than other portions of the sealing strip portion;

[0083] (2) The electricity storage device according to (1), wherein the fastening portion is formed in a portion other than the weak sealing portion.

[0084] (3) The sealing band portion is a first sealing portion where the first packaging material and the second packaging material are adhered to the electrode portion; The electricity storage device according to (1) or (2), further comprising a second sealing portion that is a portion different from the first sealing portion and that directly bonds the first packaging material and the second packaging material.

[0085] (4) The electricity storage device according to (3), wherein the weak sealing portion is formed in a longitudinal center portion of a portion of the second sealing portion along the longitudinal direction of the electrode portion.

[0086] (5) The portion of the terminal portion to which the first sealing portion is bonded has a plurality of through holes that penetrate in the stacking direction, The electricity storage device according to (3) or (4), wherein the fastening member passes through the through hole to form the fastening portion.

[0087] (6) The electricity storage device according to any one of (1) to (5), wherein the fastening member is a wire having a higher heat resistance temperature than the outer layer member.

[0088] (7) The electricity storage device according to any one of (1) to (6), wherein the fastening member is a staple.

[0089] (8) A plurality of the electricity storage devices according to any one of (1) to (7), a housing case capable of housing the power storage devices arranged in the stacking direction, At least a part of the weak sealing portion of the sealing strip is exposed to the outside of the storage case.

[0090] (9) The storage module according to (8), a drive motor supplied with power from the power storage device assembly; a main body in which the power storage device assembly and the drive motor are disposed, and a moving body driven by the drive motor, A movable body in which at least a portion of the second sealing portion where the weak sealing portion is formed communicates with the outside from a lower portion of the main body. [Industrial Applicability]

[0091] The present invention can be widely used in mobile objects equipped with electrically powered devices. [Explanation of symbols]

[0092] 100 Energy Storage Module 200 cases 201 Torso 202 Occlusion 203 Bottom plate part 204 Slit 300 Electric Vehicles 301 wheels 302 Drive motor 311 Through hole 312 Mesh section 400 Energy Storage Pack 1, 1A, 1B, 1C Energy storage device 10, 10A, 10B Exterior material 11 Storage section 11a opening 12, 12A, 12B Sealed strip 121, 121A, 121B 1st sealing part 122, 122A 2nd sealing part 123 Fastening part 1221 Long side 1222 Short side 124 Wire rod 125 Fastening part 126 Fastening part 127 Staples 13 Weak sealing part 131 Weak sealing part 132 Weak sealing part 133 Weak sealing part 141 1st packaging material 142 Second packaging material 15 Flange 16 Lid 20, 20A storage element 21 Positive electrode plate 22 negative electrode plate 23 Separator 30, 30A, 30B terminal section 31, 31A, 31B Positive terminal 32, 32A, 32A positive terminal 40 Resin sheet 41 Base material layer 42 Barrier Layer 43 Heat adhesive resin layer 50 tab film

Claims

1. an elongated electrode portion in which positive electrode plates and negative electrode plates are alternately stacked with intermediate members interposed therebetween; an exterior member including a first packaging material and a second packaging material that cover the electrode portion from both outer sides in the stacking direction of the electrode portion; a terminal portion electrically connected to each of the positive electrode plate and the negative electrode plate, The exterior member is a housing portion that houses the electrode portion; a sealing belt portion connected to at least a part of the outer edge of the containing portion and directly or indirectly joining the first packaging material and the second packaging material to seal the containing portion, The sealing strip is a fastening portion that applies a fastening force in a stacking direction to the first packaging material and the second packaging material by a fastening member that penetrates and fastens the first packaging material and the second packaging material; a weak seal portion where the bonding strength between the first packaging material and the second packaging material is weaker than other portions of the sealing strip portion, The fastening portion is formed in a portion other than the weak sealing portion of the electricity storage device.

2. The sealing strip is a first sealing portion where the first packaging material and the second packaging material are adhered to the electrode portion; The power storage device according to claim 1 , further comprising a second sealing portion that is a portion different from the first sealing portion and that directly bonds the first packaging material and the second packaging material.

3. The power storage device according to claim 2 , wherein the weak sealing portion is formed in a portion of the second sealing portion along a longitudinal direction of the electrode portion.

4. a portion of the terminal portion to which the first sealing portion is bonded has a plurality of through holes that penetrate the portion in the stacking direction; The power storage device according to claim 2 , wherein the fastening member passes through the through-hole to form the fastening portion.

5. The electricity storage device according to claim 1 , wherein the fastening member is a wire having a higher heat resistance temperature than the exterior member.

6. The power storage device according to claim 1 , wherein the fastening member is a staple.

7. a plurality of the electricity storage devices according to any one of claims 1 to 6; a housing case capable of housing the power storage devices arranged in the stacking direction, At least a part of the weak sealing portion of the sealing strip is exposed to the outside of the storage case.

8. The energy storage module according to claim 7; a drive motor supplied with power from the power storage module; a main body in which the power storage module and the drive motor are disposed, and a moving body driven by the drive motor, A movable body in which at least the portion where the weak sealing portion is formed communicates from the lower part of the main body to the outside.

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