Laminated battery

Abstract

The invention relates to a laminated battery. The present disclosure provides a laminated battery in which there is little possibility of corrosion cutting of a positive electrode collector terminal before the battery is fully discharged, and in which it is possible to suppress contact between saline water and an electrode laminate in a charged state. A laminated cell (1) according to the present disclosure has an electrode laminate (10), a negative electrode current collector terminal (20) electrically connected to a negative electrode current collector of the electrode laminate, a positive electrode current collector terminal (30) electrically connected to a positive electrode current collector of the electrode laminate, and a laminated film (40) sealing the electrode laminate. The positive electrode current collector terminal is formed of a metal that can be electrically corroded by the discharge potential of the electrode laminate, (i) the volume of the positive electrode current collector terminal is larger than the volume that can be electrically corroded by the capacitance of the electrode laminate, and / or (ii) the positive electrode current collector terminal has a structure in which, at a position sealed by the laminated film, the positive electrode current collector terminal extends toward the end on the side that is not electrically connected to the positive electrode current collector. The sectional area is increased.

Description

Technical Field

[0001] The present disclosure relates to stacked batteries. Background Art

[0002] As disclosed in Patent Document 1, a laminated battery is known, that is, a battery including, 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 and sealing the electrode laminate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-103291 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Batteries are sometimes exposed to salt water due to car crashes and natural disasters. In this regard, the inventors of the present application have found that a predetermined metal constituting a positive electrode current collector terminal may be electrochemically corroded due to a short circuit via salt water, and as a result, the positive electrode current collector terminal may be corroded and cut off (completely corroded) before the battery is fully discharged, and salt water may penetrate into the laminated film and contact the electrode laminate in a charged state.

[0008] An object of the present disclosure is to provide a laminated battery in which the possibility of a positive electrode current collecting terminal being corroded and cut off before the battery is fully discharged is small and contact of salt water with a charged electrode laminated body can be suppressed.

[0009] Means for solving problems

[0010] The inventors of the present application have found that the above-mentioned problems can be solved by the following means.

[0011] <Scheme 1>

[0012] A stacked battery, comprising: an electrode stack, a negative collector terminal electrically connected to the negative collector of the electrode stack, a positive collector terminal electrically connected to the positive collector of the electrode stack, and a stacking film sealing the electrode stack, wherein the positive collector terminal is formed of a metal that can be corroded by the discharge potential of the electrode stack, (i) the volume of the positive collector terminal is larger than the volume that can be corroded by the capacitance of the electrode stack, and / or (ii) the positive collector terminal has the following structure: at a position sealed by the stacking film, the cross-sectional area increases toward the end of the side that is not electrically connected to the positive collector.

[0013] <Scheme 2>

[0014] The stacked battery according to claim 1, which satisfies the above (i).

[0015] <Scheme 3>

[0016] The stacked battery according to claim 1, which satisfies the above (ii).

[0017] <Scheme 4>

[0018] The stacked battery according to Option 3, wherein the structure is a step height difference structure or a conical structure.

[0019] <Scheme 5>

[0020] The stacked battery according to any one of aspects 1 to 4, which is a sulfide-based solid battery.

[0021] Effects of the Invention

[0022] According to the present disclosure, it is possible to provide a laminated battery in which the possibility of the positive electrode current collecting terminal being corroded and cut off before the battery is fully discharged and contact of salt water with a charged electrode laminate can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic plan view showing an example of a laminated battery of the present disclosure.

[0024] Figure 2 This is a schematic side view showing an example of a laminated battery of the present disclosure, with the vicinity of a positive electrode current collecting terminal enlarged.

[0025] Figure 3 This is a schematic side view showing an example of a laminated battery of the present disclosure, with the vicinity of a positive electrode current collecting terminal enlarged.

[0026] Figure 4 It is a schematic side view showing an example of a conventional laminated battery with the vicinity of a positive electrode current collecting terminal enlarged.

[0027] Figure 5 It is a graph showing the relationship between the battery capacity and the volume of aluminum required to consume the battery capacity.

[0028] Description of Reference Numerals

[0029] 1 Battery

[0030] 10 Electrode stack

[0031] 20 Negative electrode collector terminal

[0032] 30 Positive electrode collector terminal

[0033] 40 Laminated Film DETAILED DESCRIPTION

[0034] The following is a detailed description of the embodiments of the present disclosure. Note that the present disclosure is not limited to the following embodiments, and can be implemented with various modifications within the scope of the disclosed gist.

[0035] Laminated battery

[0036] The stacked battery disclosed in the present invention comprises: an electrode stack, a negative electrode collector terminal electrically connected to the negative electrode collector of the electrode stack, a positive electrode collector terminal electrically connected to the positive electrode collector of the electrode stack, and a stacked film sealing the electrode stack. The positive electrode collector terminal is formed of a metal that can be corroded by the discharge potential of the electrode stack, (i) the volume of the positive electrode collector terminal is larger than the volume that can be corroded by the capacitance of the electrode stack, and / or (ii) the positive electrode collector terminal has the following structure: at a position sealed by the stacked film, the cross-sectional area increases toward the end of the side that is not electrically connected to the positive electrode collector.

[0037] When a battery is exposed to salt water due to a car crash, a tsunami or other natural disaster, the following reaction may occur due to a short circuit between the positive electrode current collector terminal and the negative electrode current collector terminal of the battery via the salt water (when the positive electrode current collector terminal is made of aluminum (Al)):

[0038] (Positive electrode)Al→Al 3+ +3e - 、2H2O→4H + +4e - +O2(↑) … (a)

[0039] (Negative electrode) 2H2O+2e - →2OH - +H2(↑) … (b)

[0040] That is, at the negative electrode current collector terminal of the battery, as shown in the above formula (b), only gaseous hydrogen is generated, while at the positive electrode current collector terminal of the battery, as shown in the above formula (a), metal such as aluminum (Al) constituting the current collector terminal may electrochemically corrode (galvanic corrosion). Figure 4 As shown, in the case of a positive electrode collector terminal that does not have the volume required to consume the battery capacity, the positive electrode collector terminal corrodes and cuts off (completely corrodes) before the battery is fully discharged, and salt water may penetrate into the laminate film from the position where the positive electrode collector terminal is located, and the salt water may contact the charged electrode laminate.

[0041] In this regard, the inventors of the present application have found that the above-mentioned problem can be solved by increasing the volume of the positive electrode current collecting terminal.

[0042] In addition, if Figure 4As shown, when the thickness of the positive electrode current collecting terminal is insufficient, oxygen generated by corrosion accumulates near the positive electrode current collecting terminal. Therefore, the corrosion reaction of the positive electrode current collecting terminal, that is, the discharge stops, and the battery capacity is maintained.

[0043] In this regard, the inventors of the present application have found that the above-mentioned problem can be suppressed by working on the shape of the positive electrode collector terminal. Specifically, without intending to be bound by any theory, it is believed that by making the positive electrode collector terminal into the following structure: at the position where the laminated film is sealed, the cross-sectional area of ​​the end portion of the side that is not electrically connected to the positive electrode collector is increased, it is possible to suppress the oxygen generated by corrosion from being retained near the positive electrode collector terminal, thereby effectively reducing the capacity of the battery without stopping the discharge.

[0044] The laminated battery disclosed in the present invention may be a liquid battery or a solid battery. It should be noted that, with respect to the present invention, a "solid battery" refers to a battery that uses at least a solid electrolyte as an electrolyte, and therefore, a solid battery may use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. In addition, the solid battery disclosed in the present invention may be an all-solid battery, that is, a battery that uses only a solid electrolyte as an electrolyte.

[0045] The battery of the present disclosure may be a lithium ion secondary battery. As the purpose of the battery, for example, the power supply of vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), electric vehicles (BEV), gasoline vehicles, and diesel vehicles can be listed. It is particularly preferably used as a driving power supply for hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) or electric vehicles (BEV). In addition, the battery of the present disclosure can be used as a power supply for mobile bodies other than vehicles (such as railways, ships, and aircraft), and can also be used as a power supply for electrical products such as information processing devices.

[0046] The laminated battery disclosed in the present invention will be described below with reference to the accompanying drawings. Note that the dimensional relationships in the drawings do not reflect the actual dimensional relationships.

[0047] like Figure 1 As shown, the laminated battery 1 of the present disclosure includes an electrode laminate 10 , a negative electrode collector terminal 20 electrically connected to the negative electrode collector of the electrode laminate 10 , a positive electrode collector terminal 30 electrically connected to the positive electrode collector of the electrode laminate 10 , and a laminate film 40 sealing the electrode laminate 10 .

[0048] <Electrode stack>

[0049] The electrode stack 10 functions as a power generation element of the battery 1 .

[0050] The electrode stack 10 includes a negative electrode collector and a positive electrode collector. The electrode stack 10 may include a negative electrode collector, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive electrode collector in this order.

[0051] There is no particular limitation on the shape of the electrode stack 10. For example, it may have a top portion, a bottom portion opposite to the top portion, and four side portions connecting the top portion and the bottom portion. There is no particular limitation on the shape of the top portion. For example, quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms may be listed. In addition, the shape of the top portion may be a polygon other than a quadrilateral, or a shape having a curve such as a circle. In addition, the shape of the bottom portion is the same as that of the top portion. There is no particular limitation on the shape of the side portions. For example, quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms may be listed.

[0052] 〈Negative electrode collector terminal〉

[0053] The negative electrode current collector terminal 20 is electrically connected to the negative electrode current collector of the electrode stack 10 .

[0054] The material of the negative electrode current collector terminal 20 is not particularly limited as long as it has a current collecting function, and for example, it can be the same metal material as the negative electrode current collector.

[0055] The size, shape, etc. of the negative electrode current collector terminal 20 are not particularly limited.

[0056] 〈Positive electrode current collector terminal〉

[0057] The positive electrode current collector terminal 30 is electrically connected to the positive electrode current collector of the electrode stack 10 .

[0058] The positive electrode current collector terminal 30 is formed of a metal that can be corroded by the discharge potential of the electrode stack 10. Examples of the metal that can be corroded by the discharge potential of the electrode stack 10 include aluminum, but are not limited thereto.

[0059] like Figure 2 As shown, in the laminated battery 1 of the present disclosure, (i) the volume of the positive electrode collector terminal 30 is larger than the volume that can be corroded by the capacitance of the electrode laminate 10, and / or Figure 3 As shown, (ii) the positive electrode current collector terminal 30 has a structure in which the cross-sectional area increases toward the end portion on the side not electrically connected to the positive electrode current collector at the position sealed by the laminate film 40 .

[0060] In one embodiment, the laminated battery 1 of the present disclosure satisfies the above (i). It is believed that by making it such a structure, it is possible to prevent "the positive electrode collector terminal 30 corrodes and cuts before the battery 1 is fully discharged, and salt water penetrates into the laminated film from the position where the positive electrode collector terminal 30 is located, resulting in contact between salt water and the charged electrode laminate 10" from occurring.

[0061] The volume that is larger than the volume that can be corroded by the capacitance of the electrode stack 10, that is, the volume of the positive electrode current collector terminal 30 required to completely consume the battery capacity, can be calculated as follows. First, the coulomb amount (unit: C) is calculated from the current value (unit: A) and the discharge time (unit: s) of the battery 1 during discharge. Furthermore, the amount of substance of the required electrons (unit: mol) is calculated from the calculated coulomb amount and the Faraday constant (unit: C / mol). For example, in the case where the material constituting the positive electrode current collector terminal 30 is Al, based on the oxidation reaction formula of Al, the amount of substance of the required electrons is converted into the amount of substance of Al (unit: mol). Then, based on the atomic weight of Al (unit: g) and the density of Al (unit: g / cm 3 ), convert the required amount of Al substance, and calculate the required volume of Al (unit: cm 3 ).

[0062] For reference, Table 1 shows the volume of Al required for a predetermined battery capacity calculated by the above method.

[0063]

Table 1

[0064] Battery capacity [Ah] 1 50 100 500 Coulomb quantity[C] 3600 180000 360000 1800000 Amount of substance required for electrons [mol] 0.04 1.87 3.73 18.66 Amount of Al required [mol] 0.01 0.62 1.24 6.22 Required weight of Al [g] 0.34 16.79 33.58 167.9 <![CDATA[Volume of Al required [cm 3 > 0.1 6 12 62

[0065] The relationship between the battery capacity in the above table and the required volume of Al is shown in a coordinate diagram. Figure 5 According to the linear approximation of the coordinate graph, the relationship between the battery capacity and the required volume of Al is expressed by the following formula (1):

[0066] y=0.1244x…(1)

[0067] (In formula (1), y is the required volume of Al and x is the battery capacity.)

[0068] In one embodiment, the laminated battery 1 of the present disclosure satisfies the above (ii). It is believed that such a configuration can suppress the accumulation of oxygen generated by corrosion of the positive electrode current collector terminal 30 near the positive electrode current collector terminal 30, thereby effectively reducing the battery capacity without stopping discharge.

[0069] In the embodiment satisfying the above condition (ii), the structure of the positive electrode current collector terminal 30 may be a step height difference structure (see Figure 3(a)) or a conical structure (ref. Figure 3 (b)).

[0070] 〈Laminated Film〉

[0071] The laminate film 40 seals the electrode stack 10. The laminate film 40 can seal the electrode stack 10 while sealing the negative electrode collector terminal 20 and the positive electrode collector terminal 30. Specifically, the laminate film 40 can wind the electrode stack 10 with the negative electrode collector terminal 20 and the positive electrode collector terminal 30, and seal the electrode stack 10 with the negative electrode collector terminal 20 and the positive electrode collector terminal 30. In addition, the laminate film 40 can be composed of a first film and a second film. In this case, the first film and the second film can clamp the electrode stack 10 with the negative electrode collector terminal 20 and the positive electrode collector terminal 30 from the top and bottom of the stacking direction of the electrode stack 10, and seal the electrode stack 10 with the negative electrode collector terminal 20 and the positive electrode collector terminal 30.

[0072] The laminate film 40 may have a fusion resin layer, a metal layer, and a protective resin layer in 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.

[0073] The stacked battery disclosed in the present invention may be a sulfide-based solid battery. If the battery is a sulfide-based solid battery, a liquid containing sulfide ions (sulfide ions) may be produced when salt water contacts the electrode stack, and in this case, post-processing becomes difficult. According to the stacked battery disclosed in the present invention, the contact between salt water and the electrode stack can be suppressed, so that the liquid containing sulfide ions can be less likely to be produced.

Claims

1. A laminated battery comprising: an electrode laminate, a negative electrode collector terminal electrically connected to a negative electrode collector of the electrode laminate, a positive electrode collector terminal electrically connected to a positive electrode collector of the electrode laminate, and a laminate film sealing the electrode laminate, The positive electrode current collector terminal is formed of a metal that can be corroded by the discharge potential of the electrode stack. (i) the volume of the positive electrode current collector terminal is larger than the volume that can be corroded by the 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 on a side not electrically connected to the positive electrode current collector at a position sealed by the laminate film.

2. The stacked battery according to claim 1, which satisfies the condition (i). The stacked battery according to claim 1 , which satisfies the condition (ii).

4. The laminated battery according to claim 3, wherein: The structure is a step height difference structure or a cone structure. 5 . The stacked battery according to claim 1 , which is a sulfide-based solid battery.

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