JP7147445B2 - battery device - Google Patents

Description

The present invention relates to battery devices.

When the temperature of a battery containing an electrolytic solution rises abnormally, there is a concern that combustible gas may be generated due to the decomposition of the electrolytic solution or the like, and the battery may ignite. This abnormal rise in temperature occurs when, for example, the battery is subjected to a strong impact or pressure, or when a sharp object pierces the battery, the separator in the battery housing breaks and the positive electrode and the negative electrode are internally short-circuited. Due to the internal short-circuit, a large current flows through the short-circuited portion to generate heat, and the decomposition reaction of the electrolytic solution and the reaction between the electrolytic solution and the negative electrode or the positive electrode proceed.

Regarding measures against ignition of the battery, Patent Document 1 discloses that a small chamber containing a combustion mitigating agent is provided in the housing of the lithium ion battery, and the combustion mitigating agent is destroyed by increasing the temperature or pressure in the battery housing. It is described to release Further, Patent Literature 2 describes that the surfaces of the electrodes in the battery housing are coated with heat-absorbing inorganic particles to suppress sudden heat generation and ignition when an internal short circuit occurs.

JP 2017-525108 A Japanese Patent No. 6091742

The above prior art anti-ignition measures are to suppress heat generation and ignition during an internal short circuit with a combustion modifier or an endothermic inorganic substance. However, since ignition and combustion of batteries are caused by the presence of combustible substances, there is a concern that further ignition and combustion may occur as long as the combustible substances exist, even if the ignition is temporarily suppressed.

Therefore, the present invention focuses on the fact that ignition and combustion of batteries are caused by the presence of combustible substances, and solves the problem of ignition and combustion of batteries from the viewpoint of removing the combustible substances.

In order to solve the above problems, the present invention utilizes a catalyst to remove combustibles in the battery housing.

That is, in the battery device disclosed herein, the positive electrode and the negative electrode are insulated by a separator and housed in the battery housing together with the electrolyte,
A catalyst is provided in the battery housing for oxidatively decomposing combustible gas generated as the electrolyte is decomposed ,
an electric heater for heating the catalyst;
a heater circuit connected to the positive electrode and the negative electrode for energizing the electric heater;
impact prediction means for predicting the possibility that an impact will be applied to the battery housing from the outside;
switch means for closing the heater circuit so that the electric heater is energized when the possibility is predicted by the impact prediction means .

According to this, even if the electrolytic solution is decomposed and a combustible gas is generated due to heat generation due to an internal short circuit of the battery or the like, the combustible gas is oxidatively decomposed by the catalyst. Therefore, it is advantageous for suppression of ignition and combustion of the battery.

In one embodiment, each of the positive electrode, the negative electrode, and the separator is sheet-shaped, and the positive electrode and the negative electrode are wound or laminated in the battery housing while being insulated from each other with the separator interposed therebetween. is provided.

In the case of such a battery structure, contact between the positive electrode and the negative electrode, that is, an internal short circuit, is likely to occur when the separator breaks when an external impact is applied to the battery, or when the separator is deteriorated and damaged due to heat generation inside the battery. In such a battery, even if the electrolyte is decomposed by the heat generated by the internal short circuit and a combustible gas is produced, the catalyst decomposes the gas, which is advantageous in suppressing ignition and combustion of the battery.

In one embodiment, the catalyst is formed by supporting a catalyst metal on a sheet-like carrier, and is arranged at least in the upper part of the cell housing.

The combustible gas generated by the decomposition of the electrolytic solution tends to rise and accumulate in the upper part of the battery housing.

In one embodiment, at least part of the carrier is a metal carrier, and the metal carrier portion of the catalyst is arranged from the side to the top in the cell housing.

When an impact is applied to the battery from the side, heat is generated due to an internal short circuit in the side portion of the battery housing. Since the metal carrier has better heat conductivity than the ceramic carrier, the temperature of the catalyst tends to rise quickly due to the heat generation at the side portion inside the battery housing. Since the heat is efficiently transmitted from the side portion of the catalyst to the upper portion of the cell housing through the metal carrier, , the catalyst quickly reaches the activation temperature, which is advantageous for decomposing and removing combustible gas.

Also, the battery device
an electric heater for heating the catalyst;
a heater circuit connected to the positive electrode and the negative electrode for energizing the electric heater;
impact prediction means for predicting the possibility that an impact will be applied to the battery housing from the outside;
switch means for closing the heater circuit so that the electric heater is energized when the possibility is predicted by the impact prediction means.

When an impact is applied to the battery housing from the outside, there is a high risk of generating combustible gas due to an internal short circuit. On the other hand, when it is predicted that there is a possibility that a shock will be applied to the battery housing, the energization circuit is closed and the electric heater is activated, so that the temperature of the catalyst can be quickly raised and the combustible It is advantageous for decomposing and removing toxic gases.

According to the present invention, the catalyst for oxidatively decomposing the combustible gas generated by the decomposition of the electrolyte is provided in the battery housing. Even if a combustible gas is generated, the combustible gas is oxidatively decomposed by the catalyst, which is advantageous in suppressing ignition and combustion of the battery.

1 is a perspective view of a cell of a battery device according to an embodiment; FIG. The perspective view which shows the internal structure of the same cell. FIG. 3 is a cross-sectional view showing a part of the electrode-wound body of the same cell. The longitudinal cross-sectional view of the same cell. The block diagram of the heater operating system of the same battery apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses.

A battery cell 1 shown in FIG. 1 is a cell constituting a lithium ion battery device. For example, in a hybrid vehicle (not shown) equipped with a wheel driving engine and a wheel driving motor, the lithium ion battery device has a function of discharging to the driving motor and a function of storing electric power converted by the engine regenerative energy system. is mounted as a secondary battery device having

Although the shape of the battery cell 1 of this embodiment is rectangular, the present invention is not limited to a rectangular cell shape, and other shapes such as a cylindrical shape and a pouch shape may be used. The battery cell 1 includes a battery housing 3 that accommodates the electrode-wound body 2 and the like shown in FIG. A positive electrode cell terminal 4 , a negative electrode cell terminal 5 and a safety valve (gas discharge valve) 6 are provided on the upper surface of the battery housing 3 .

Although the battery cell 1 can constitute a battery device by itself, by connecting the positive electrode cell terminals 4 and the negative electrode cell terminals 5 of each of the plurality of battery cells 1, the battery device can be formed by the plurality of battery cells 1. can also be configured. The safety valve 6 opens when the internal pressure rises when the battery is abnormal, and prevents the battery housing 3 from bursting.

As shown in FIGS. 2 and 3, the electrode-wound body 2 is formed by winding a positive electrode sheet 11 and a negative electrode sheet 12 in a state insulated from each other with a sheet-shaped separator 13 interposed therebetween.

The positive electrode sheet 11 is formed by mixing a positive electrode active material such as lithium cobaltate and an auxiliary agent (a binder such as polyvinylidene fluoride and a conductive agent such as carbon black) and applying the mixture to a current collector such as an aluminum foil. . The negative electrode sheet 12 is formed by mixing a negative electrode active material such as a graphite-based carbon material and an auxiliary agent (a binder such as styrene-butadiene rubber and a conductive agent such as carbon black) and applying the mixture to a current collector such as copper foil. It becomes The separator 13 is made of a single-layer or laminated microporous film of polyolefin such as polypropylene or polyethylene, and is impregnated with a non-aqueous electrolyte containing an organic compound as a main component.

The non-aqueous electrolyte is obtained by dissolving a lithium salt (supporting electrolyte) in a non-aqueous solvent, and additives are added as necessary.

The type of non-aqueous solvent is not particularly limited, and cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl Chain carbonic acid esters such as carbonate (DMC), cyclic carboxylic acid esters such as γ-butyrolactone (GBL), γ-valerolactone (GVL), and the like can be mentioned. The non-aqueous solvent may be used singly or in combination of two or more.

Preferred lithium salts include LiPF ₆ , LiPO ₂ F ₂ , LiBF ₄ , LiN(SO ₂ F) ₂ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ and the like. Lithium salt can be used individually by 1 type, or can be used in combination of 2 or more type.

Ends of the positive electrode sheet 11 and the negative electrode sheet 12 protrude laterally from both sides of the electrode-wound body 2 and are connected to the positive electrode tab lead 14 and the negative electrode tab lead 15, respectively. The upper end portions of the positive electrode tab lead 14 and the negative electrode tab lead 15 each extend toward the other side along the upper surface of the electrode-wound body 2, and the positive electrode cell terminal 4 and the negative electrode cell terminal 5 are connected to the upper end portions thereof. there is

As shown in FIG. 2, the electrode-wound body 2 has its entire outer peripheral surface covered with an external catalyst sheet 16 in which a catalyst metal having an oxidation catalytic activity is supported on a sheet-like carrier. That is, the external catalyst sheet 16 is provided not only on the upper part inside the battery housing 3 but also on the side part inside the battery housing 3 . The carrier of the external catalyst sheet 16 is a metallic carrier made of stainless steel. Noble metals such as Pt, Pd, and Rh are employed as catalyst metals. Among them, Pd, which has a high oxidation catalytic ability, is preferable as the catalyst metal. The external catalyst sheet 16 and the positive electrode sheet 11 or the negative electrode sheet 12 at the outermost periphery of the electrode-wound body 2 are insulated by the separator 13 of the electrode-wound body 2 .

In addition, between the tab leads 14 and 15 above the electrode-wound body 2, that is, between the electrode-wound body 2 and the safety valve 6, which is the upper part in the battery housing 3, a catalyst metal having the oxidation catalytic ability is placed on the plate-shaped carrier. A plate-like upper catalyst 17 carrying Further, as shown in FIG. 4 , an internal catalyst sheet 18 is also arranged inside the electrode-wound body 2 in a state of being insulated from the positive electrode sheet 11 and the negative electrode sheet 12 . Like the outer catalyst sheet 16, the inner catalyst sheet 18 is formed by supporting a catalyst metal having the oxidation catalytic ability on a sheet-like metal carrier.

In this case, since the upper catalyst 17 and the external catalyst sheet 16 are in contact with each other at the upper portion (near the upper end) of the external catalyst sheet 16, the heat transferred to the external catalyst sheet 16 due to an internal short circuit, which will be described later, is transferred to the upper catalyst 17. can be quickly transmitted to the upper catalyst 17, contributing to the early activation of the upper catalyst 17.

Further, as shown in FIG. 4 , a sheet-like electric heater 21 is provided between the outer peripheral surface of the electrode-wound body 2 and the external catalyst sheet 16 . In this embodiment, the electric heater 21 is disposed between the side surface of the electrode-wound body 2 and the external catalyst sheet 16, and is different from the positive electrode sheet 11 or the negative electrode sheet 12 at the outermost periphery of the electrode-wound body 2. It is insulated by the separator 13 of the electrode winding body 2 .

As shown in FIG. 5, the battery device includes a heater circuit 22 for energizing an electric heater 21, an impact prediction means 23 for predicting the possibility that an external impact will be applied to the battery housing 3, and an impact prediction means. A switch means 24 for closing the heater circuit 22 so that the electric heater 21 is energized when the possibility is predicted by 23 .

The heater circuit 22 is configured by connecting an electric heater 21 to the positive electrode cell terminal 4 and the negative electrode cell terminal 5 of the battery cell 1 , and the heater circuit 22 is provided with a switch means 24 .

The impact prediction means 23 includes an obstacle detection sensor 25 for detecting obstacles around the vehicle, and based on the detection signal of the obstacle detection sensor 25, whether or not there is a possibility that the vehicle will collide with the obstacle. and a control unit 26 for outputting a closing signal to the switch means 24 when a collision is predicted.

The obstacle detection sensor 25 is composed of a millimeter wave radar, a laser radar, or the like, and detects obstacles around the vehicle, as well as the distance and relative speed between the obstacle and the vehicle. The control unit 26 uses a microcomputer and predicts collision by dividing the distance between the vehicle and the obstacle by the relative speed between the vehicle and the obstacle when the vehicle speed is equal to or higher than a predetermined vehicle speed. When the time is calculated and the collision prediction time becomes equal to or less than a predetermined time, the vehicle may collide with the obstacle, and therefore the battery housing 3 of the battery cell 1 may be impacted. A close signal is output to the switch means 24.

The operating system of the electric heater 21 shown in FIG. 5 is an example of an assembled battery in which a plurality of battery cells 1 are connected and used. A plurality of battery cells 1 are connected to form a discharge circuit 28 that discharges to an external load 27 . The control unit 26 outputs a closing signal to the switch means 24 of the heater circuit 22 of each battery cell 1 . Note that the illustration of the charging circuit is omitted.

Therefore, according to the above-described embodiment, when the separator 13 is torn due to external impact applied to the battery cell 1, or when the separator 13 is deteriorated and damaged due to heat generation inside the cell and an internal short circuit occurs, the following occurs. , ignition and combustion of the battery cell 1 are suppressed. First, the heat generated by the internal short circuit decomposes the solvent in the electrolytic solution to generate combustible gas. For example, in the case of DEC (diethyl carbonate), its decomposition produces butane, a combustible gas. Further, due to the heat generation, the temperature of the catalyst sheets 16, 18 and the upper catalyst 17 rises to the temperature at which they become active. Therefore, when the combustible gas (hydrocarbon) comes into contact with the catalyst sheets 16, 18 or the upper catalyst 17 at its generating portion, or rises in the cell housing 3, the combustible gas (hydrocarbon) 17 and is oxidatively decomposed into nonflammable CO ₂ and H ₂ O.

Here, when a shock is applied to the battery cell 1 from the outside, the separator 13 is easily damaged at the outer peripheral portion of the electrode-wound body 2, resulting in an internal short circuit. On the other hand, since the external catalyst sheet 16 covers the outer peripheral portion of the electrode-wound body 3 , the heat generated by the internal short circuit is easily transferred to the external catalyst sheet 16 . As a result, the temperature of the external catalyst sheet 16 rises in the heat generating portion. Since the external catalyst sheet 16 uses a metal carrier as a catalyst carrier, the temperature of the external catalyst sheet 16 is likely to rise due to the heat generation, and the heat is easily transmitted to the entire external catalyst sheet 16 .

For example, when an impact is applied to the battery housing 3 from the side, heat is generated due to an internal short circuit in the side portion of the battery housing 3, and the heat is disposed in the side portion of the external catalyst sheet 16. from the part to the part disposed in the upper part in the battery housing 3 through the metal carrier. Therefore, the entire outer catalyst sheet 16 quickly reaches the activation temperature, which is advantageous for the oxidative decomposition of the combustible gas by the outer catalyst sheet 16 .

In addition, in the above-described embodiment, the catalyst sheet 18 is arranged not only on the outer periphery of the electrode-wound body 3 but also on the inside of the electrode-wound body 3. As it rises, it comes into contact with the inner catalyst sheet 18 and is oxidatively decomposed. Furthermore, the combustible gas rising inside the battery housing 3 accumulates in the upper part of the battery housing 3. Since the upper catalyst 17 is arranged in the upper part, the combustible gas can be reliably decomposed and removed. be advantageous.

Further, in the above embodiment, the electric heater 21 is provided between the electrode-wound body 2 and the external catalyst sheet 16, and the switch means 24 of the heater circuit 22 is closed when a collision of the own vehicle is predicted. Then, the electric heater 21 generates heat in advance. Therefore, since the temperature of the external catalyst sheet 16 can be quickly raised to the activation temperature, when combustible gas is generated due to an internal short circuit due to collision, the combustible gas can be quickly decomposed and removed, and the battery can be This is advantageous for preventing the cell 1 from igniting and burning.

Although the battery cell 1 of the above embodiment is of the wound type, in the present invention, the battery may be of the laminated type in which the positive electrode sheet and the negative electrode sheet are alternately laminated with a separator sandwiched between the both sheets. It may be in any form, and the form of the battery does not matter.

In the above-described embodiment, a plurality of types of catalysts 16 to 18 are arranged in the battery housing 3, but it is also possible to adopt a configuration in which only one of them is arranged, or another arrangement form according to the battery form. can also be taken.

Moreover, the catalyst carrier is not limited to a metal carrier, and may be a ceramic carrier.

REFERENCE SIGNS LIST 1 battery cell 2 electrode winding body 3 battery housing 11 positive electrode sheet 12 negative electrode sheet 13 separator 16 external catalyst sheet 17 upper catalyst 18 internal catalyst sheet 21 electric heater 22 heater circuit 23 impact prediction means 24 switch means

Claims (4)

In a battery device in which a positive electrode and a negative electrode are insulated by a separator and accommodated in a battery housing together with an electrolyte,
A catalyst is provided in the battery housing for oxidatively decomposing combustible gas generated as the electrolyte is decomposed ,
an electric heater for heating the catalyst;
a heater circuit connected to the positive electrode and the negative electrode for energizing the electric heater;
impact prediction means for predicting the possibility that an impact will be applied to the battery housing from the outside;
and switch means for closing the heater circuit so that the electric heater is energized when the possibility is predicted by the impact prediction means . In claim 1,
Each of the positive electrode, the negative electrode, and the separator is sheet-like, and the positive electrode and the negative electrode are provided in the battery housing in a wound or laminated state in a state in which the positive electrode and the negative electrode are insulated from each other with the separator interposed therebetween. A battery device characterized by: In claim 1 or claim 2,
The battery device according to claim 1, wherein the catalyst comprises a sheet-like carrier carrying a catalyst metal, and is arranged at least in the upper part of the battery housing. In claim 3,
A battery device, wherein at least part of the carrier is a metal carrier, and the metal carrier portion of the catalyst is arranged from the side to the upper part in the battery housing.

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