Laminate battery

Abstract

To provide a laminate battery in which the risk of corrosion of a positive electrode current collecting terminal before the battery is fully discharged is small and the contact between saline water and an electrode multilayer body in a charged state can be suppressed.SOLUTION: A laminate battery 1 according to the present disclosure includes an electrode multilayer body 10, a negative electrode current collecting terminal 20 electrically connected to a negative electrode current collector of the electrode multilayer body, a positive electrode current collecting terminal 30 electrically connected to a positive electrode current collector of the electrode multilayer body, and a laminate film 40 that seals the electrode multilayer body. The positive electrode current collecting terminal is formed of a metal that can be electrically corroded depending on the discharging potential of the electrode multilayer body, and has a structure in which (i) the volume of the positive electrode current collecting terminal is larger than the volume that can be electrically corroded depending on the electric capacity of the electrode multilayer body and / or (ii) the cross-sectional area of the positive electrode current collecting terminal increases toward an end part on a side that is not electrically connected to the positive electrode current collector at a position sealed with the laminate film.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a laminate battery. [Background technology]

[0002] As disclosed in Patent Document 1, laminate batteries are known, that is, batteries having, for example, an electrode laminate, a current collecting terminal electrically connected to the electrode laminate, and a laminate film covering the electrode laminate and a portion of the current collecting terminal to seal the electrode laminate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-103291 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, batteries may be exposed to salt water due to accidents involving automobiles falling, natural disasters, etc. In this regard, the present inventors have found that a specific metal constituting the positive electrode current collector terminal may be electrochemically corroded by short circuit via salt water, and as a result, the positive electrode current collector terminal may completely corrode before the battery is completely discharged, causing salt water to penetrate into the laminate film, and the salt water may come into contact with the electrode laminate in a charged state.

[0005] The present disclosure aims to provide a laminate battery that reduces the risk of the positive electrode collector terminal corroding completely before the battery is completely discharged and that can suppress contact between salt water and an electrode laminate in a charged state. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by the following means.

[0007] <Aspect 1> An electrode stack, a negative electrode current collector terminal electrically connected to a negative electrode current collector of the electrode laminate; a positive electrode current collector terminal electrically connected to the positive electrode current collector of the electrode stack; and A laminate film sealing the electrode stack having the positive electrode current collector terminal is formed of a metal that can be electrolytically corroded by a discharge potential of the electrode stack, (i) the volume of the positive electrode current collector terminal is larger than the volume that can be electrolytically corroded by the electrical capacitance of the electrode laminate, and / or (ii) the positive electrode current collector terminal has a structure in which a cross-sectional area increases toward an end portion not electrically connected to the positive electrode current collector at a position sealed by the laminate film; Laminated battery. <Aspect 2> The laminate battery according to embodiment 1, which satisfies the above (i). <Aspect 3> The laminate battery according to embodiment 1, which satisfies the above (ii). <Aspect 4> 4. The laminate battery according to claim 3, wherein the structure is a stepped structure or a tapered structure. <Aspect 5> The laminate battery according to any one of aspects 1 to 4, which is a sulfide-based solid battery. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a laminate battery in which there is little risk of the positive electrode collector terminal corroding completely before the battery is completely discharged, and which can suppress contact between salt water and the electrode laminate in a charged state. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view showing an example of a laminate battery according to the present disclosure. [Diagram 2]FIG. 2 is a schematic side view showing an example of a laminate battery of the present disclosure, with an enlarged view of the vicinity of the positive electrode current collector terminal. [Diagram 3] FIG. 3 is a schematic side view showing an example of a laminate battery of the present disclosure, with an enlarged view of the vicinity of the positive electrode current collector terminal. [Figure 4] FIG. 4 is a schematic side view showing an example of a conventional laminate battery with an enlarged view of the positive electrode current collector terminal and its vicinity. [Diagram 5] FIG. 5 is a graph showing the relationship between battery capacity and the volume of aluminum required to consume the battery capacity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure.

[0011] Laminated battery The laminate battery of the present disclosure includes an electrode laminate, a negative electrode current collector terminal electrically connected to a negative electrode current collector of the electrode laminate, a positive electrode current collector terminal electrically connected to a positive electrode current collector of the electrode laminate, and a laminate film sealing the electrode laminate. The positive electrode current collector terminal is made of a metal that can be electrolytically corroded by the discharge potential of the electrode laminate, and (i) the volume of the positive electrode current collector terminal is larger than the volume that can be electrolytically corroded by the electric capacity of the electrode laminate, and / or (ii) the positive electrode current collector terminal has a structure in which, at the position where it is sealed by the laminate film, the cross-sectional area increases toward the end on the side not electrically connected to the positive electrode current collector.

[0012] If a battery is exposed to salt water due to a natural disaster such as a falling car or a tsunami, the following reaction may occur at the positive and negative collector terminals of the battery due to a short circuit via the salt water (if the positive collector terminal is made of aluminum (Al)): (Positive electrode) Al→Al 3+ +3e - , 2H 2 O→4H + +4e -+O 2 (↑) … (a) (Negative electrode) 2H 2 O+2e - →2OH - +H 2 (↑) … (b)

[0013] That is, in the negative electrode current collector terminal of the battery, only gaseous hydrogen is generated as shown in the above formula (b), whereas in the positive electrode current collector terminal of the battery, metals such as aluminum (Al) constituting the current collector terminal may electrochemically corrode (galvanic corrosion) as shown in the above formula (a). Therefore, as shown in Fig. 4, in the case of a positive electrode current collector terminal that does not have the volume necessary to consume the capacity of the battery, the positive electrode current collector terminal corrodes completely before the battery is completely discharged, and salt water may penetrate into the laminate film from the place where the positive electrode current collector terminal was, causing the salt water to come into contact with the electrode laminate in the charged state.

[0014] In regard to this, the present inventors have found that the above problem can be solved by increasing the volume of the positive electrode current collector terminal.

[0015] Furthermore, as shown in Figure 4, if the thickness of the positive current collector terminal is insufficient, oxygen gas generated by corrosion may accumulate near the positive current collector terminal, causing the corrosion reaction of the positive current collector terminal, i.e., discharge, to stop, and the battery capacity may remain.

[0016] In this regard, the present inventors have found that the above problem can be suppressed by devising a shape of the positive electrode current collector terminal. Specifically, without intending to be bound by any theory, it is believed that the positive electrode current collector terminal has a structure in which the cross-sectional area increases toward the end on the side not electrically connected to the positive electrode current collector at the position sealed by the laminate film, thereby suppressing the accumulation of oxygen gas generated due to corrosion near the positive electrode current collector terminal, and therefore the capacity of the battery can be efficiently reduced without stopping discharge.

[0017] The laminated battery of the present disclosure may be a liquid battery or a solid-state battery. In the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as an electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. The solid-state battery of the present disclosure may also be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as an electrolyte.

[0018] The battery of the present disclosure may be a lithium-ion secondary battery. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery of the present disclosure may also be used as a power source for moving objects other than vehicles (e.g., railways, ships, and aircraft), and may also be used as a power source for electrical appliances such as information processing devices.

[0019] Hereinafter, the laminate battery of the present disclosure will be described with reference to the drawings. Note that the dimensional relationships in each drawing do not reflect the actual dimensional relationships.

[0020] As shown in FIG. 1 , a laminate battery 1 of the present disclosure includes an electrode laminate 10, a negative electrode current collector terminal 20 electrically connected to a negative electrode current collector of the electrode laminate 10, a positive electrode current collector terminal 30 electrically connected to a positive electrode current collector of the electrode laminate 10, and a laminate film 40 that seals the electrode laminate 10.

[0021] <Electrode laminate> The electrode stack 10 functions as a power generating element of the battery 1 .

[0022] The electrode laminate 10 has a negative electrode current collector and a positive electrode current collector. The electrode laminate 10 may have a negative electrode current collector, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in this order.

[0023] The shape of the electrode laminate 10 is not particularly limited, but may have, for example, a top surface portion, a bottom surface portion facing the top surface portion, and four side surfaces connecting the top surface portion and the bottom surface portion. The shape of the top surface portion is not particularly limited, but may be, for example, a quadrangle such as a square, a rectangle, a rhombus, a trapezoid, or a parallelogram. The shape of the top surface portion may be a polygon other than a quadrangle, or may be a shape having a curve such as a circle. The shape of the bottom surface portion is the same as that of the top surface portion. The shape of the side surface portion is not particularly limited, but may be, for example, a quadrangle such as a square, a rectangle, a rhombus, a trapezoid, or a parallelogram.

[0024] <Negative current collecting terminal> The negative electrode current collector terminal 20 is electrically connected to the negative electrode current collector of the electrode stack 10 .

[0025] The material of the negative electrode current collector terminal 20 is not particularly limited as long as it has a current collecting function, and may be, for example, the same metal material as the negative electrode current collector.

[0026] The size, shape, etc. of the negative electrode current collector terminal 20 are not particularly limited.

[0027] <Positive electrode current collector terminal> The positive electrode current collector terminal 30 is electrically connected to the positive electrode current collector of the electrode stack 10 .

[0028] The positive electrode current collector terminal 30 is formed of a metal that can be electrolytically corroded by the discharge potential of the electrode stack 10. An example of a metal that can be electrolytically corroded by the discharge potential of the electrode stack 10 is aluminum, but is not limited to this.

[0029] As shown in FIG. 2, in the laminate battery 1 of the present disclosure, (i) the volume of the positive electrode current collector terminal 30 is larger than the volume that can be electrolytically corroded by the electrical capacitance of the electrode laminate 10, and / or, as shown in FIG. 3, (ii) the positive electrode current collector terminal 30 has a structure in which, at the position sealed by the laminate film 40, the cross-sectional area increases toward the end on the side that is not electrically connected to the positive electrode current collector.

[0030] In one embodiment, the laminate battery 1 of the present disclosure satisfies the above (i). With such a configuration, it is considered that the positive electrode collector terminal 30 is completely corroded before the battery 1 is completely discharged, and salt water is unlikely to come into contact with the electrode laminate 10 in a charged state due to the salt water penetrating into the laminate film from the location where the positive electrode collector terminal 30 was previously located.

[0031] The volume of the positive electrode current collecting terminal 30, which is larger than the volume that can be electrolytically corroded by the electric capacity of the electrode laminate 10, i.e., which is required to consume the entire battery capacity, can be calculated as follows. First, the amount of coulombs (unit: C) is calculated from the current value (unit: A) and discharge time (unit: s) during discharge of the battery 1. Furthermore, the amount of electrons (unit: mol) required is calculated from the calculated amount of coulombs and the Faraday constant (unit: C / mol). Here, for example, when the material constituting the positive electrode current collecting terminal 30 is Al, the amount of electrons required is converted into the amount of Al required (unit: mol) based on the oxidation reaction formula of Al. The amount of Al required is then calculated based on the atomic weight of Al (unit: g) and the density of Al (unit: g / cm 3 ) to calculate the required volume of Al (unit: cm 3 ) can be calculated.

[0032] For reference, the volume of Al required for a given battery capacity, calculated by the above method, is shown in Table 1.

[0033] [Table 1]

[0034] A graph showing the relationship between the battery capacity and the required volume of Al in the above table is shown in Figure 5. According to the linear approximation of this graph, the relationship between the battery capacity and the required volume of Al is expressed by the following formula (1): y=0.1244x … (1) (In equation (1), y is the required volume of Al and x is the battery capacity.)

[0035] In one embodiment, the laminate battery 1 of the present disclosure satisfies the above condition (ii). With this configuration, it is believed that oxygen gas generated due to corrosion of the positive electrode current collector terminal 30 can be prevented from accumulating near the positive electrode current collector terminal 30, and therefore the capacity of the battery can be efficiently reduced without stopping discharge.

[0036] In an embodiment that satisfies the above condition (ii), the positive electrode current collecting terminal 30 may have a stepped structure (see FIG. 3(a)) or a tapered structure (see FIG. 3(b)).

[0037] <Lamination film> The laminate film 40 seals the electrode laminate 10. The laminate film 40 may seal the electrode laminate 10 together with the negative electrode collector terminal 20 and the positive electrode collector terminal 30. Specifically, the laminate film 40 may be formed by winding the electrode laminate 10, the negative electrode collector terminal 20, and the positive electrode collector terminal 30, and may seal the electrode laminate 10 together with the negative electrode collector terminal 20 and the positive electrode collector terminal 30. The laminate film 40 may be composed of a first and a second film, and in this case, the first and second films may sandwich the electrode laminate 10, the negative electrode collector terminal 20, and the positive electrode collector terminal 30 from above and below in the stacking direction of the electrode laminate 10, and may seal the electrode laminate 10 together with the negative electrode collector terminal 20 and the positive electrode collector terminal 30.

[0038] The laminate film 40 may have a fusion resin layer, a metal layer, and a protective resin layer in this order along the thickness direction. Examples of materials for the fusion resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon.

[0039] The laminated battery of the present disclosure may be a sulfide-based solid battery. If the battery is a sulfide-based solid battery, contact between salt water and the electrode laminate may produce a liquid containing dissolved sulfide ions, making post-treatment difficult. The laminated battery of the present disclosure can suppress contact between salt water and the electrode laminate, making it difficult to produce a liquid containing dissolved sulfide ions. [Explanation of symbols]

[0040] 1 battery 10 Electrode laminate 20 Negative current collector terminal 30 Positive collector terminal 40 Laminating Film

Claims

1. An electrode stack, a negative electrode current collector terminal electrically connected to a negative electrode current collector of the electrode laminate; a positive electrode current collector terminal electrically connected to the positive electrode current collector of the electrode stack; and A laminate film sealing the electrode stack having the positive electrode current collector terminal is formed of a metal that can be electrolytically corroded by a discharge potential of the electrode stack, (i) the volume of the positive electrode current collector terminal is larger than the volume that can be electrolytically corroded by the electrical capacitance of the electrode stack, and / or (ii) the positive electrode current collector terminal has a structure in which a cross-sectional area increases toward an end portion not electrically connected to the positive electrode current collector at a position sealed by the laminate film; Laminated battery.

2. The laminate battery according to claim 1 , which satisfies the above (i).

3. The laminate battery according to claim 1 , which satisfies the above (ii).

4. The laminate battery according to claim 3 , wherein the structure is a stepped structure or a tapered structure.

5. The laminate battery according to any one of claims 1 to 4, which is a sulfide-based solid battery.

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