JP7040121B2 - Battery - Google Patents

Description

The present disclosure relates to a cell, and particularly to a cell mounted in a vehicle.

Conventionally, as a document in which a cell cell provided with a short-circuit element is disclosed, for example, Japanese Patent Application Laid-Open No. 2014-022284 (Patent Document 1) can be mentioned.

In the cell cell disclosed in Patent Document 1, a short-circuit element is inserted in the central portion (inside the winding core) of the electrode body wound around the winding core in a state where the positive electrode, the separator and the negative electrode are laminated. ..

In the short-circuit element, an insulator and a low melting point alloy layer are sandwiched between a first conductor connected to the positive electrode of the electrode body and a second conductor connected to the negative electrode of the electrode body. An expansion member that expands near a predetermined temperature is arranged on the outside of at least one of the first conductor and the second conductor.

When the electrode body generates heat at the time of abnormality and the temperature becomes close to a predetermined temperature, the expansion member expands so that the first conductor and the second conductor come close to each other in a state where the low melting point alloy layer is melted, so that the electrode body expands. The positive and negative electrodes of the are short-circuited.

Japanese Unexamined Patent Publication No. 2014-022284

However, in the short-circuit element disclosed in Patent Document 1, the expansion suppressing member that suppresses the expansion of the short-circuit element as a whole includes a first conductor, a second conductor, an insulator, and a low melting point alloy. It is provided to enclose. Therefore, the configuration of the short-circuit element becomes complicated and the short-circuit element becomes large.

As the capacity of the battery increases, it becomes difficult to arrange a plurality of short-circuit elements having the above-mentioned configuration in order to effectively utilize the inside of the storage case for accommodating the electrode body. From the viewpoint of space saving, the short-circuit element is not suitable.

Further, the short-circuit element is arranged in the central portion of the electrode body. Therefore, in an assembled battery in which a plurality of cells are arranged side by side, the short-circuit element is arranged at a considerable distance from the cells arranged next to each other.

In this case, if the other cells generate heat due to an abnormality, it takes time for the heat to be transferred from the adjacent cells to the short-circuit element. This may delay the operation of the short-circuit element.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to quickly operate a short-circuit element when heat is transferred from the outside while using a short-circuit element having a simple structure. It is to provide a cell that can be used.

A cell based on the present disclosure includes an electrode body in which a positive electrode and a negative electrode are laminated in a stacking direction with a separator interposed therebetween, a plurality of short-circuit elements configured so that the positive electrode and the negative electrode can be short-circuited, and the electrode body and the above. A storage case for accommodating a plurality of short-circuit elements is provided. The short-circuit element is sandwiched between the positive electrode conductor electrically connected to the positive electrode, the negative electrode conductor electrically connected to the negative electrode, and the positive electrode conductor and the negative electrode conductor in contact with each other. Includes a negative temperature characteristic member whose resistance value decreases as the temperature rises. The plurality of short-circuit elements are arranged so as to face the electrode body at least on both ends of the electrode body in the stacking direction.

As described above, the configuration of the short-circuit element can be simplified by configuring the short-circuit element so that the negative temperature characteristic member is sandwiched between the positive electrode conductor and the negative electrode conductor. As a result, the short-circuit element can be made thinner, and a plurality of short-circuit elements can be arranged in the housing case.

As described above, when a plurality of short-circuit elements are arranged so as to face the electrode body at least on both ends of the electrode body in the stacking direction of the positive electrode, the separator, and the negative electrode, the plurality of cells are arranged in one direction. When constructing an assembled battery, the short-circuit element can be arranged close to the adjacent cell. As a result, when another cell generates heat due to an abnormality or the like and heat is transferred from the adjacent cell, the heat can be quickly transferred to the short-circuit element. As a result, the short-circuit element can be operated quickly.

According to the present disclosure, it is possible to provide a cell cell capable of quickly operating the short-circuit element when heat is transferred from the outside while using the short-circuit element having a simple configuration.

It is a schematic diagram which shows the assembled battery which concerns on embodiment. It is a schematic diagram which shows the cell battery which concerns on embodiment. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. It is an exploded perspective view which disassembled and arranged the electrode body and a plurality of short-circuit elements which concerns on embodiment. It is a schematic diagram which shows the short-circuit element which concerns on embodiment. It is a figure which shows the state of the verification experiment which carried out in order to confirm the effect of embodiment. It is a figure which shows the condition and the result of the verification experiment which carried out to confirm the effect of embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are designated by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Assembled battery)
FIG. 1 is a schematic view showing an assembled battery according to an embodiment. The assembled battery 1 according to the embodiment will be described with reference to FIG.

The assembled battery 1 is mainly mounted on a vehicle such as a hybrid vehicle and an electric vehicle. The assembled battery 1 is configured by electrically connecting a plurality of cell cells 10 in series, whereby the assembled battery 1 can output a large voltage. The assembled battery 1 supplies electric power to the electric motor for driving the vehicle. On the other hand, the assembled battery 1 charges the electric power generated by the electric motor by regenerative braking or the like.

The assembled battery 1 includes a plurality of cells 10 arranged side by side in one direction. A spacer 70 (see FIG. 6) is arranged between the plurality of cells 10. The cell 10 is a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The cell 10 has, for example, a square shape.

The cell 10 includes a positive electrode terminal 12 and a negative electrode terminal 13. A plurality of cells 10 are arranged so that the positive electrode terminal 12 of one of the cells 10 adjacent to each other and the negative electrode terminal 13 of the other cell 10 face each other. The plurality of cell cells 10 are electrically connected in series by a bus bar (not shown).

(Batteries)
FIG. 2 is a schematic view showing a cell cell according to the embodiment. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. FIG. 4 is an exploded perspective view in which the electrode body and a plurality of short-circuit elements according to the embodiment are disassembled and arranged. The cell 10 according to the embodiment will be described with reference to FIGS. 2 to 4.

As shown in FIG. 2, the cell 10 includes an electrode body 30, a plurality of short-circuit elements 20, and a housing case 11.

The storage case 11 has, for example, a square shape (flat rectangular parallelepiped shape). The housing case 11 is provided with a positive electrode terminal 12 and a negative electrode terminal 13. The housing case 11 houses the electrode body 30 and a plurality of short-circuit elements 20 inside. The storage case 11 may also contain an electrolytic solution or the like inside.

As shown in FIGS. 2 to 4, the electrode body 30 includes a positive electrode plate 40 as a positive electrode, a negative electrode plate 50 as a negative electrode, and a separator 60. The electrode body 30 is configured by laminating the positive electrode plate 40 and the negative electrode plate 50 in the laminating direction with the separator 60 interposed therebetween.

The positive electrode plate 40 is an electrode plate having a positive polarity. The planar shape of the positive electrode plate 40 is, for example, a rectangular shape. The positive electrode plate 40 typically includes a positive electrode current collector 41 and a positive electrode active material layer 42. The portion of the positive electrode current collector 41 exposed from the positive electrode active material layer 42 is electrically connected to the positive electrode terminal 12.

The positive electrode current collector 41 has a thickness of, for example, about 10 to 30 μm. The positive electrode current collector 41 may be, for example, an Al foil or the like. The Al foil may be a pure Al foil or an Al alloy foil.

The positive electrode active material layer 42 is formed on the surface of the positive electrode current collector 41. The positive electrode active material layer 42 may be formed on only one side of the positive electrode current collector 41, or may be formed on both sides. The positive electrode active material layer 42 has a thickness of, for example, about 10 to 200 μm.

The positive electrode active material layer 42 includes positive electrode active material particles, conductive particles, and a binder. The positive electrode active material particles are, for example, a compound represented by LiCoO ₂ , LiNiO ₂ , or the general formula LiNi _a Co _b O ₂ (where a + b = 1, 0 <a <1, 0 <b <1 in the formula). , LiMnO ₂ , LiMn ₂ O ₄ , general formula LiNi _a Cob Mn _c O ₂ (however, in the formula, a + b + _c = 1, 0 <a <1, 0 <b <1, 0 <c <1). The represented compound, LiFePO4 or the like may be used. Here, examples of the compound represented by the general formula LiNi _a Co _b Mn _c O ₂ include LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and the like. One kind of positive electrode active material particles may be used alone, or two or more kinds of positive electrode active material particles may be used in combination.

The conductive particles may be, for example, acetylene black, thermal black, furnace black, vapor phase grown carbon fiber (VGCF), graphite, graphene flakes and the like. One kind of conductive particles may be used alone, or two or more kinds of conductive particles may be used in combination.

The binder may be, for example, PVdF, PTFE or the like. One type of binder may be used alone, or two or more types of binders may be used in combination.

The negative electrode plate 50 is an electrode plate having a negative polarity. The planar shape of the negative electrode plate 50 is, for example, a rectangular shape. The negative electrode plate 50 typically includes a negative electrode current collector 51 and a negative electrode active material layer 52. The portion of the negative electrode current collector 51 exposed from the negative electrode active material layer 52 is electrically connected to the negative electrode terminal 13.

The negative electrode current collector 51 has a thickness of, for example, about 10 to 30 μm. The negative electrode current collector 51 may be, for example, a copper (Cu) foil or the like. The Cu foil may be a pure Cu foil or a Cu alloy foil.

The negative electrode active material layer 52 is formed on the surface of the negative electrode current collector 51. The negative electrode active material layer 52 may be formed on only one side of the negative electrode current collector 51, or may be formed on both sides. The negative electrode active material layer 52 has a thickness of, for example, about 10 to 200 μm.

The negative electrode active material layer 52 includes, for example, negative electrode active material particles and a binder. The negative electrode active material particles may be, for example, graphite particles, easily graphitized carbon particles, non-graphitizable carbon particles, silicon particles, silicon oxide particles, tin particles, tin oxide particles and the like. One type of negative electrode active material particles may be used alone, or two or more types of negative electrode active material particles may be used in combination.

The binder may be, for example, CMC, SBR, or the like. One type of binder may be used alone, or two or more types of binders may be used in combination.

The separator 60 is made of an insulating material. The separator 60 is arranged between the positive electrode plate 40 and the negative electrode plate 50. The separator 60 is also arranged between the electrode body 30 and the short-circuit element 20.

The separator 60 has a porous structure, and ions and electrons can pass through the pores in the separator 60. Therefore, ions and electrons can move from the positive electrode active material layer 42 to the negative electrode active material layer 52, or from the negative electrode active material layer 52 to the positive electrode active material layer 42.

The plurality of short-circuit elements 20 are configured so that the positive electrode plate 40 and the negative electrode plate 50 can be short-circuited. The plurality of short-circuit elements 20 are arranged so as to be arranged in the stacking direction of the positive electrode plate 40, the separator 60, and the negative electrode plate 50. The plurality of short-circuit elements 20 are arranged so as to face the electrode body 30 at least on both ends of the electrode body 30 in the stacking direction.

In the embodiment, three short-circuit elements 20 are provided. Two short-circuit elements 20 are arranged on both ends of the electrode body 30 in the stacking direction. These two short-circuit elements 20 are arranged between the electrode body 30 and the housing case 11, respectively. The remaining one short-circuit element 20 is arranged in the central portion of the electrode body 30.

The number of short-circuit elements 20 is not limited to three. As described above, the number of the short-circuit elements 20 may be two or more as long as the short-circuit elements 20 are arranged so as to face the electrode body 30 at least on both ends of the electrode body 30 in the stacking direction.

(Short circuit element)
FIG. 5 is a schematic view showing a short-circuit element according to the embodiment. The configuration of the short-circuit element 20 according to the embodiment will be described with reference to FIG.

The short-circuit element 20 includes a first conductor 21 as a positive electrode conductor, a second conductor 22 as a negative electrode conductor, and a negative temperature characteristic member 23.

The first conductor 21 is made of, for example, a metal foil. As the metal foil for the positive electrode, for example, the same member as the positive electrode current collector 41 may be used. The metal foil for the positive electrode is, for example, an Al foil or the like. The Al foil may be a pure Al foil or an Al alloy foil.

The second conductor 22 is made of, for example, a metal foil. As the metal foil for the negative electrode, for example, the same member as the negative electrode current collector 51 may be used. The metal foil for the negative electrode is, for example, a copper (Cu) foil or the like. The Cu foil may be a pure Cu foil or a Cu alloy foil.

The negative temperature characteristic member 23 has a plate-like shape. The negative temperature characteristic member 23 has a thickness of, for example, about 5 to 30 μm.

The negative temperature characteristic member 23 is sandwiched in contact with the first conductor 21 and the second conductor 22. The first conductor 21 is arranged so that the portion exposed from the negative temperature characteristic member 23 overlaps the positive electrode current collector 41 of the portion exposed from the positive electrode active material layer 42. The second conductor 22 is arranged so that the portion exposed from the negative temperature characteristic member 23 overlaps the negative electrode current collector 51 in the portion exposed from the negative electrode active material layer 52.

The negative temperature characteristic member 23 is a member whose resistance value decreases as the temperature rises. As the negative temperature characteristic member 23, for example, silicon carbide (SiC) can be adopted. The negative temperature characteristic member 23 is not limited to the silicon carbide, and may be a CTR thermistor or the like.

As described above, in the cell 10 according to the embodiment, the short-circuit element 20 is configured to sandwich the negative temperature characteristic member 23 between the first conductor 21 and the second conductor 22. The configuration of the short-circuit element 20 can be simplified. As a result, the short-circuit element 20 can be made thinner, and even when the electrode body is made thicker or the size of the housing case 11 is reduced as the capacity is increased, a plurality of short-circuit elements 20 are contained in the storage case 11. The short-circuit element 20 can be arranged.

Further, when a plurality of short-circuit elements 20 are arranged so as to face the electrode body 30 at least on both ends of the electrode body 30 in the stacking direction, a plurality of cell cells 10 are arranged in one direction to form the assembled battery 1. The short-circuit element 20 can be arranged so as to be close to the cell cells arranged next to each other. As a result, when the other cell 10 generates heat due to an abnormality or the like and heat is transferred from the adjacent cell, the heat can be quickly transferred to the short-circuit element 20. As a result, the short-circuit element 20 can be operated quickly.

(Verification experiment)
FIG. 6 is a diagram showing a state of a verification experiment carried out to confirm the effect of the embodiment. FIG. 7 is a diagram showing the conditions and results of the verification experiment carried out to confirm the effect of the embodiment. A verification experiment performed to confirm the effect of the embodiment will be described with reference to FIGS. 6 and 7.

As shown in FIGS. 6 and 7, in the verification experiment, the assembled batteries according to Comparative Example 1, Comparative Example 2, and Example 1 were prepared, and a nail piercing test was carried out in these assembled batteries. Specifically, a nail 80 having a tip angle of 30 degrees and a nail diameter of φ3 mm was passed through a cell battery arranged in the center of the assembled battery at a speed of 10 mm / sec.

The size of the storage case for the cell was 148 mm in width, 26.4 mm in depth, and 91 mm in height. The capacity of the cell was set to 50 Ah. The positive electrode plate 40 was made of Al foil, and its thickness was 12 μm. The negative electrode plate 50 was made of Cu foil, and its thickness was 10 μm.

The charge rate (State Of Charge, SOC) of the cell was set to 100%, and the assembled battery was placed in a constant temperature bath set at 25 ° C.

FIG. 6 illustrates the assembled battery 1 according to the first embodiment. The assembled battery 1 according to the first embodiment was prepared by arranging seven cell batteries 10 according to the embodiment in a direction parallel to the stacking direction. That is, the assembled battery 1 according to the first embodiment was prepared by arranging seven cell cells 10 in which the short-circuit elements 20 are arranged on both ends and the center of the electrode body 30. SiC was used as the negative temperature toxic member 23 in the short-circuit element 20, and the thickness thereof was set to 5 μm.

The assembled battery according to Comparative Example 1 was prepared by arranging seven single batteries not provided with the short-circuit element 20 in the same manner as in Example 1. The assembled battery according to Comparative Example 2 was prepared by arranging seven single batteries in which the short-circuit element 20 is arranged only in the central portion of the electrode body 30 in the same manner as in Example 1.

In a cell with a nail stuck in it, heat is generated due to a forced internal short circuit, and the generated heat is sequentially transferred to the adjacent cell. Therefore, the assembled batteries according to Comparative Example 1, Comparative Example 2, and Example 1 were evaluated by confirming the number of single batteries that emit smoke by transmitting the heat generated by nailing.

As shown in FIG. 7, in the assembled battery according to Comparative Example 1, all the cells (6 cells) other than the battery in which the nail was pierced smoked. Also in the assembled battery according to Comparative Example 2, all the cells (6 cells) other than the battery in which the nail was pierced smoked.

On the other hand, in the assembled battery according to the first embodiment, only two cells adjacent to the cell in which the nail was pierced emitted smoke, and the other cells did not emit smoke.

From the above results, by arranging a plurality of short-circuit elements 20 so as to face the electrode body 30 at least on both ends of the electrode body 30 in the stacking direction, the short-circuit elements 20 are quickly operated, and other cells emit smoke. It was confirmed that it suppresses the operation.

As described above, the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims and includes all modifications within the meaning and scope equivalent to the scope of claims.

1 set battery, 10 cell, 11 housing case, 12 positive electrode terminal, 13 negative electrode terminal, 20 short-circuit element, 21 1st conductor, 22 2nd conductor, 23 negative temperature characteristic member, 30 electrode body, 40 positive electrode plate, 41 Positive electrode current collector, 42 Positive electrode active material layer, 50 Negative electrode plate, 51 Negative electrode current collector, 52 Negative electrode active material layer, 60 separator, 70 spacer, 80 nails.

Claims (1)

An electrode body in which the positive electrode and the negative electrode are laminated in the stacking direction with a separator interposed therebetween,
A plurality of short-circuiting elements configured to short-circuit the positive electrode and the negative electrode, and
A housing case for accommodating the electrode body and the plurality of short-circuit elements is provided.
The short-circuit element is sandwiched between a positive electrode conductor electrically connected to the positive electrode, a negative electrode conductor electrically connected to the negative electrode, and the positive electrode conductor and the negative electrode conductor in contact with each other. Including a negative temperature characteristic member whose resistance value decreases as the temperature rises,
The plurality of short-circuit elements are arranged so as to face the electrode body at least on both outer sides of the electrode body in the stacking direction.

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