WO2014068866A1

WO2014068866A1 - Vehicle having storage battery module mounted therein

Info

Publication number: WO2014068866A1
Application number: PCT/JP2013/006083
Authority: WO
Inventors: 敏宏坂谷; 裕政杉井; 越智　誠; 龍二川瀬
Original assignee: 三洋電機株式会社
Priority date: 2012-10-30
Filing date: 2013-10-11
Publication date: 2014-05-08
Also published as: JP2016012946A

Abstract

Provided is a vehicle comprising safe nickel metal hydride storage batteries, whereby the hydrogen concentration does not exceed an explosion limit in a space having arranged therein a storage battery module comprising a plurality of nickel metal hydride storage batteries, even without the provision of an exhaust duct or exhaust fan in the space. This vehicle has mounted therein the storage battery module having a plurality of nickel metal hydride storage batteries connected in series, and is configured such that the spatial volume (Y) (L) inside the vehicle fulfils the relationship Y≥X×N×41.0, when the capacitance of the nickel metal hydride storage batteries is X (Ah) and the number of said batteries is N. As a result, the hydrogen concentration inside the vehicle does not exceed 3 vol%.

Description

Vehicle with storage battery module

The present invention relates to a vehicle equipped with a storage battery module including a large number of nickel metal hydride storage batteries.

Hybrid electric vehicles (HEV: Hybrid Electric Vehicle), plug-in hybrid electric vehicles (PHEV: Plug-in Hybrid Electric Vehicle), electric vehicles (EV: Electric Vehicle), and other applications that require large current charging / discharging, or idle lead-acid batteries In vehicles with a stop function and a deceleration energy regeneration system that recovers energy during deceleration as electrical energy, nickel-metal hydride storage batteries and lithium secondary batteries are often used in addition to lead storage batteries that are widely used as power sources for general vehicles. ing. Among these, the nickel-metal hydride storage battery has the advantage of being excellent in safety and being inexpensive, although the energy density per unit mass is small as compared with the lithium secondary battery.

Since each nickel metal hydride storage battery has a nominal voltage of 1.2 V, a storage battery module in which several tens to several hundreds of nickel hydride storage batteries are connected in series or in series and parallel is used when mounted on a vehicle. When using a storage battery module with a large number of nickel metal hydride storage batteries in this way, current concentrates on a specific battery, internal short circuit, overcharge, overdischarge, etc. occur, and the safety valve provided in the nickel metal hydride storage battery May operate, or the exterior body may be damaged and leak.

Also, nickel-metal hydride batteries generate hydrogen gas when overcharged or overdischarged. Since the amount of generated hydrogen gas is proportional to the number of nickel-metal hydride storage batteries, a storage battery module having a large number of nickel-metal hydride storage batteries also increases the amount of hydrogen gas generated during overcharge or overdischarge. Therefore, in a vehicle in which a storage battery module including a large number of nickel metal hydride storage batteries is arranged, it is desired that the indoor hydrogen concentration be maintained below the explosion limit.

For the purpose of coping with such a situation, in vehicles such as HEV, PHEV, EV and the like using a storage battery module including a large number of nickel metal hydride storage batteries, it is also shown in, for example, Patent Documents 1 and 2 below. As described above, an exhaust duct or an exhaust fan is provided in a space where the storage battery module is disposed.

JP 2011-253817 A Japanese Patent Laid-Open No. 2003-100302

If an exhaust duct or exhaust fan is installed in a space where a storage battery module with a large number of nickel-metal hydride storage batteries is installed, it is possible to avoid an increase in the hydrogen concentration in the space, and hydrogen fills the vehicle and causes an explosion limit. The possibility of reaching 4 vol% or more is reduced. However, if these configurations are provided, a hydrogen gas detector and control means may be required depending on the case, resulting in high costs.

According to one aspect of the present invention, the hydrogen concentration in the space does not exceed the explosion limit without providing an exhaust duct or an exhaust fan in a space where a storage battery module including a large number of nickel hydride storage batteries is disposed. A vehicle including a safe nickel-metal hydride storage battery can be provided.

According to one aspect of the invention,
A storage battery module in which a plurality of nickel metal hydride storage batteries are connected in series is mounted in the vehicle,
When the capacity of the nickel metal hydride storage battery is X (Ah) and the solid number is N (pieces),
The space volume Y (L) in the vehicle is
Y ≧ X × N × 41.0
A vehicle equipped with a nickel-metal hydride storage battery that satisfies the above relationship is provided.

In the present invention, a storage battery module in which N sets of N-metal hydride storage batteries with a capacity of XAh are connected in series is connected in series with N (M × X) Ah nickel-metal hydride storage batteries. That's fine.

According to the vehicle on which the nickel-metal hydride storage battery of one aspect of the present invention is mounted, even if overcharging up to three times the full charge of the nickel-metal hydride storage battery, that is, 3X (Ah), is performed. Since the hydrogen concentration of the battery is only 3 vol% or less, which is less than the explosion limit of 4 vol%, a vehicle equipped with a nickel-metal hydride storage battery excellent in safety can be obtained.

It is a longitudinal cross-sectional view of the cylindrical nickel-metal hydride storage battery used with the storage battery module of the experiment example. It is a figure which shows schematic structure of the rear seat vicinity of the vehicle which uses the storage battery module of an experiment example.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the following embodiment is illustrated for the purpose of understanding the technical idea of the present invention, and is not intended to specify the present invention as the embodiment, and the present invention is not limited to the scope of the claims. The present invention can equally be applied to those in which various modifications are made without departing from the technical idea shown in.

[Production of nickel positive electrode]
A nickel positive electrode is a nickel sintered substrate that has a nickel sintered substrate filled with a positive electrode active material containing nickel hydroxide as a main component and added with any compound selected from zinc hydroxide and cobalt hydroxide. Using. In this case, the nickel sintered substrate was prepared as follows.

Nickel (Ni) powder was mixed and kneaded with methyl cellulose (MC) as a thickener, for example, a polymer hollow microsphere having a pore size of 60 μm, and water to prepare a nickel slurry. Next, after applying nickel slurry on both sides of the punching metal made of nickel-plated steel plate, it was heated at 1000 ° C in a reducing atmosphere to eliminate the thickener and polymer hollow microspheres, and to sinter the nickel powder together By doing so, a porous nickel sintered substrate was obtained. When the obtained porous nickel substrate was measured with a mercury intrusion porosimeter (Pascal 140 manufactured by Faisons Instruments), the porosity was 85%.

The resulting porous nickel sintered substrate was impregnated with a mixed aqueous solution of nickel nitrate (Ni (NO ₃ ) ₂ ) and zinc nitrate (Zn (NO ₃ ) ₂ ) or cobalt nitrate (Co (NO ₃ ) ₂ ). Then, the substrate was immersed in an alkaline solution (for example, an aqueous sodium hydroxide solution) at 80 ° C. (8 mol / L) for alkali treatment. Thereby, nickel nitrate and zinc nitrate or cobalt nitrate were converted into nickel hydroxide (Ni (OH) ₂ ), zinc hydroxide (Zn (OH) ₂ ), or cobalt hydroxide (Co (OH) ₂ ). . Thereafter, the substrate was sufficiently washed with water to remove the alkaline solution and then dried.

Such a series of positive electrode active material filling operations, such as impregnation of the impregnating liquid into the porous nickel sintered substrate, drying, immersion in an alkali treatment liquid, washing with water, and drying, are repeated experimentally in advance. A predetermined amount of the positive electrode active material was filled into a porous nickel sintered substrate.

[Preparation of hydrogen storage alloy]
The hydrogen storage alloy of the experimental example was prepared as follows. Lanthanum (La), neodymium (Nd), magnesium (Mg), nickel (Ni), and aluminum (Al) are mixed at a ratio that gives a molar ratio of the following chemical formula, this mixture is dissolved in a high-frequency induction furnace, and this is quenched. There _was prepared an ingot of hydrogen-absorbing alloy represented by _{_{_{La 0.4 Nd 0.5 Mg 0.1 Ni 3.5}}} Al 0.2. The resulting hydrogen storage alloy ingot is lower by 30 ° C. than the melting point of the hydrogen storage alloy so that the hydrogen storage pressure at 40 ° C. and H / M = 0.5 is 0.020 MPa to 0.055 MPa. Heat treatment was performed at a temperature for 10 hours.

In addition, even if the composition of the hydrogen storage alloy is the same, the equilibrium hydrogen pressure changes due to the influence of the crystal structure or the like, and the internal crystal structure changes depending on the heat treatment temperature and heat treatment time, so the equilibrium hydrogen pressure also changes. Therefore, the heat treatment temperature and heat treatment time at which a predetermined hydrogen storage pressure is obtained vary depending on the composition of the hydrogen storage alloy.

Thereafter, the hydrogen storage alloy ingot of the obtained experimental example was coarsely pulverized and then mechanically pulverized in an inert atmosphere, and the hydrogen storage alloy powder remaining between 400 mesh and 200 mesh was selected by sieving. . In addition, when the average particle diameter of the obtained hydrogen storage alloy powder was determined from the measured value of the particle size distribution using a laser diffraction / scattering particle size distribution measuring device, the average particle diameter corresponding to a mass integral of 50% (D50) was 25 μm. . This was used as the hydrogen storage alloy powder of the experimental example.

[Production of hydrogen storage alloy negative electrode]
0.5 parts by mass of SBR (styrene butadiene latex) as a water-insoluble polymer binder and CMC as a thickener for 100 parts by mass of the hydrogen storage alloy powder of the experimental example prepared as described above. 0.03 parts by mass of (carboxymethylcellulose) and an appropriate amount of pure water were added and kneaded to prepare a hydrogen storage alloy slurry. And after apply | coating the obtained hydrogen storage alloy slurry to both surfaces of the negative electrode core body which consists of punching metal (made by nickel plating steel plate), after drying at 100 degreeC and rolling so that it may become predetermined | prescribed packing density, predetermined The hydrogen storage alloy negative electrode of the experimental example was produced.

[Preparation of alkaline electrolyte]
The alkaline electrolyte is a mixed aqueous solution in which potassium hydroxide (KOH), sodium hydroxide (NaOH), and lithium hydroxide (LiOH) are adjusted to a predetermined molar ratio. What was added so that it might become 20 mg was used.

[Production of nickel metal hydride storage battery]
A separator made of a polyolefin non-woven fabric having a basis weight of 55 g / cm ² was interposed between the nickel positive electrode and the hydrogen storage alloy negative electrode manufactured as described above, and wound to prepare a spiral electrode group. At this time, at least one surface of the separator has an ammonia adsorption ability by performing a sulfonation treatment or using an ammonia adsorption ability fiber.

The positive electrode current collector was welded to the end portion of the electrode plate core of the nickel positive electrode plate exposed at the upper end surface of the spiral electrode group. On the other hand, the negative electrode current collector was welded to the end portion of the electrode core body of the hydrogen storage alloy electrode plate exposed at the lower end surface. This spiral electrode body was inserted into an outer can, the negative electrode current collector and the bottom of the can were welded, and the electrolyte was poured into the outer can. Thereafter, the sealing body was welded to the current collecting lead, the sealing portion was crimped and sealed, and four types of cylindrical nickel-metal hydride batteries each having a battery capacity of 6.0 Ah were produced.

A specific configuration of the cylindrical nickel-metal hydride storage battery manufactured as described above will be described with reference to FIG. This nickel metal hydride storage battery 10 has a wound electrode body 14 in which a nickel positive electrode 11 manufactured as described above and a hydrogen storage alloy negative electrode 12 are wound in a state of being insulated from each other via a separator 13. ing.

The nickel positive electrode 11 is mainly composed of nickel hydroxide in a porous nickel sintered body 16 formed on both surfaces of a positive electrode core 15 made of a nickel-plated steel sheet punching metal, and is composed of zinc hydroxide and cobalt hydroxide. The positive electrode active material 17 to which any one of the selected compounds is added is filled. In the hydrogen storage alloy negative electrode 12, a negative electrode mixture layer 19 having hydrogen storage alloy powder as a negative electrode active material is formed on both surfaces of a negative electrode core 18 made of a nickel-plated mild steel punching metal.

A negative electrode current collector 20 is resistance-welded to the negative electrode core 18 at the lower part of the wound electrode body 14, and a positive electrode current collector 21 is resistance-welded to the positive electrode core 15 at the upper part of the wound electrode body 14. Yes. The wound electrode body 14 is inserted into a bottomed cylindrical metal outer can 22 in which iron is nickel-plated, and spot welding is performed between the negative electrode current collector 20 and the bottom of the metal outer can 22. Has been.

On the open end side of the outer can 22, a sealing body 23 in which iron is plated with nickel is caulked and fixed with a gasket 24 being electrically insulated from the outer can 22. The positive electrode current collector 21 is welded and electrically connected to the sealing body 23. An opening 25 is provided in the center of the positive electrode current collector 21, and a valve body 26 is disposed in the opening 25 so as to block the opening 25.

Also, a positive electrode cap 27 is provided on the upper surface of the sealing body 23 so as to cover the periphery of the opening 25 and be separated from the valve body 26 by a certain distance. The positive electrode cap 27 is appropriately provided with a gas vent hole (not shown). A spring 28 is provided between the inner surface of the positive electrode cap 27 and the valve body 26, and the valve body 26 is pressed by the spring 28 so as to close the opening 25 of the sealing body 23. The valve body 26 has a function as a safety valve for releasing the internal pressure when the internal pressure of the outer can 22 becomes high.

A battery module with a nominal voltage of 24 V and 30 Ah was manufactured by using 100 nickel-metal hydride storage batteries of the experimental example having such a configuration and connecting 20 sets connected in series to each other in parallel. In HEV, PHEV, EV, etc., as shown in FIG. 2, the storage battery module is often placed on the rear trunk. Therefore, the length of the rear trunk is also 2 m × width 1.5 m × height A sealed model room having a volume of 1.2 m and a volume of 3.6 m ³ (= 3600 L) was produced, and the storage battery module of the embodiment was installed in the model room.

In addition, it is preferable to use what comprised the storage battery system connected in parallel with the lead storage battery as a storage battery module of said embodiment. The storage battery system having such a configuration can reduce the number of nickel-metal hydride storage batteries used in the storage battery module, can effectively realize the above relationship, and can further improve safety.

The module was continuously charged at a constant current of 30 A until it became three times the fully charged state, that is, until the integrated charge amount was 3 × 30 = 90 Ah, and the hydrogen concentration in the model room at that time was measured. %. Since the explosion limit of hydrogen gas is 4 vol% or higher, it was confirmed that the hydrogen concentration was below the explosion limit without exhausting the air in the model room.

A theoretical study of the principle of the present invention is as follows. Since the amount of hydrogen generated during overdischarge is smaller than that during overcharge, the following will examine the state during overcharge. Hydrogen generation during overcharge is based on the following reaction formula.
Reaction formula:
H ⁺ + e ⁻ → 1 / 2H ₂
Assuming that all of the charge capacity 3X (Ah) that has been overcharged to three times the fully charged state is consumed for the reaction, the amount of hydrogen generated per nickel-metal hydride storage battery is calculated by the following formula.
Electricity flow:
3X (Ah) = 3 × 3600X (As)
= 10800X (C)
Number of moles supported:
10800X (C) / 96485 (C / mol)
= 0.11X (mol)
Applicable volume:
0.11X (mol) /2×22.4 (L)
= 1.23X (L)
Hydrogen generation amount per storage battery module:
1.23X (L) × N
= 1.23X x N (L)
Since the explosion limit of hydrogen gas is generally 4 vol% or more, if the allowable limit is 3 vol% in consideration of safety, the required space volume Y (L) is expressed by the following equation.
1.23X × N (L) / Y (L) × 100 ≦ 3 (vol%)
Ｙ Y ≧ X × N × 41.0 (L)

Actually, not all of the current that flows during overcharging is used for hydrogen generation based on the above reaction formula, so the above Y value is overestimated. However, even if the overcharge of 3X (Ah) or more is continued, the nickel hydrogen storage battery electrolyte will be exhausted at the end, so the actual hydrogen generation amount is more than the amount shown in the above examination results. Is also greatly reduced. Therefore, as long as at least the value of Y satisfies the above relationship, the hydrogen gas concentration in the indoor air will be 3 vol% or less even without a mechanism for forcibly exhausting the air in the vehicle interior to the outside. Since it is maintained, it is clear that safety in overcharging and overdischarging is sufficiently ensured.

DESCRIPTION OF SYMBOLS 10 ... Nickel-metal hydride storage battery 11 ... Nickel positive electrode 12 ... Hydrogen storage alloy negative electrode 13 ... Separator 14 ... Winding electrode body 15 ... Positive electrode core body 16 ... Porous nickel sintered body 17 ... Positive electrode active material 18 ... Negative electrode core body 19 ... Negative electrode Mixture layer 20 ... Negative electrode current collector 21 ... Positive electrode current collector 22 ... Metal outer can 23 ... Sealing body 24 ... Gasket 25 ... Opening 26 ... Valve element 27 ... Positive electrode cap 28 ... Spring

Claims

A storage battery module in which a plurality of nickel metal hydride storage batteries are connected in series is mounted in the vehicle,
When the capacity of the nickel metal hydride storage battery is X (Ah) and the solid number is N (pieces),
The space volume Y (L) in the vehicle is
Y ≧ X × N × 41.0
A vehicle equipped with a nickel metal hydride storage battery that satisfies the above relationship.
The vehicle equipped with the nickel-metal hydride storage battery according to claim 1, wherein the vehicle is not provided with a mechanism for forcibly discharging the air in the vehicle to the outside.
The vehicle is equipped with a storage battery system in which the nickel hydride storage battery and the lead storage battery according to claim 1 or 2 are connected in parallel.