JP2011076952A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery with high safety in which damages of an electrode group in a battery and exhaust failure of an internal gas are prevented. <P>SOLUTION: The sealed battery includes an electrode group which is housed in an outer package can 1 and includes a positive electrode and a negative electrode, a battery seal 10 which is respectively electrically connected to the positive and the negative electrodes, covers the aperture of the outer package can, and has a positive electrode terminal and a negative electrode terminal, and spacers 41a, 41b which are arranged between the battery seal and the electrode group. The spacers fix the electrode group in the outer package can and have pressing plates 46a-46c with a gangway formed at a position facing the upper end face 2a of the electrode group, so that the spacers can prevent movement of the electrode group when vibration and shock are applied to the battery. Further, the electrolyte liquid filled from an electrolyte liquid injection port 20 is collected at the upper part 2a of the electrode group from the pressing plate gangway of the spacers, thereby the electrolyte liquid is uniformly impregnated from the upper end of the electrode group. Further, the gangway becomes a passage during gas exhaust and a safety valve is reliably opened. Thereby, the sealed battery with high reliability can be provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a sealed battery, and more particularly, to a structure in which an electrode group housed in a battery outer can is prevented from moving.

In recent years, nickel-metal hydride secondary batteries and lithium-ion secondary batteries have been used as power sources for electronic devices such as mobile phones and personal computers, uninterruptible power supplies for hybrid vehicles, electric vehicles, and mobile phone base stations. A sealed battery such as a water electrolyte secondary battery is expected.

Sealed batteries used in portable electronic devices are required to be smaller and lighter. On the other hand, sealed batteries typified by hybrid cars, electric cars, electric motorcycles, forklifts, etc., have been developed with larger sizes and larger capacities, especially with regard to safety and long-term reliability. Yes.

As the shape of the sealed battery, a cylindrical shape or a square shape is generally used.
It is attracting attention because of its excellent space efficiency when mounted on equipment.

These sealed batteries contain a power generation element in which an electrode group consisting of a positive electrode, a negative electrode, and a separator is impregnated with an electrolyte in a cylindrical outer can made of a metal plate, and an opening of the outer can It is sealed with a battery sealing body, and the space between the battery sealing body and the outer can opening is sealed so as to prevent leakage of electrolyte and gas. The electrode group and the external terminal are connected by a conductive tab. The conductive tab is formed by extending from the current collector plate of the electrode or by attaching the conductive tab to the current collector plate by welding. For this reason, when a sealed battery is mounted on a portable electronic device or an electric vehicle, the electrode group moves inside the battery due to the vibration or impact of the device, and the conductive tab connecting the electrode group and the external terminal is disconnected. Or bends easily.

Therefore, in order to prevent the electrode group in the case from being displaced, a spacer is provided between the electrode group and the sealing plate, so that the electrode group moves even when vibration or impact is applied to the battery. A technique for preventing this is disclosed (see Patent Document 1).

Japanese Patent Laid-Open No. 8-329911

Normally, a sealed battery such as a non-aqueous electrolyte secondary battery has an electrochemical function as a battery only when a non-aqueous electrolyte is injected. In order for the non-aqueous electrolyte to reach all of the positive electrode layer and the negative electrode layer in the wound electrode group, it is necessary for the non-aqueous electrolyte to penetrate from the upper and lower parts of the electrode group in the height direction to the center part of the electrode group. There is. And, as the electrolyte solution is sufficiently and evenly impregnated into the electrode group, battery characteristics such as charge / discharge characteristics and cycle characteristics are exhibited.

In addition, when the nonaqueous electrolyte secondary battery is stored at a high temperature in an overcharged state or a charged state, the nonaqueous solvent in the nonaqueous electrolyte solution is easily decomposed, and gas is generated inside the battery to increase the internal pressure of the battery. For this reason, when the battery internal pressure rises above a certain pressure, a safety valve is provided for discharging the generated gas to the outside of the battery. The internal gas is generated in the electrode group, flows out from the electrode group to the safety valve, and is discharged from the opened safety valve to the outside of the battery.

However, when the portion of the spacer that contacts the spiral portion of the electrode group that fixes the electrode group is plate-shaped, the electrolyte solution injected from the liquid injection port installed on the sealing plate is separated from the electrode group by the plate-shaped portion of the spacer. When the spiral part of the battery is pressed down to prevent the electrolyte group from being impregnated into the electrode group and the electrolyte solution is not uniformly impregnated into the electrode group, or when gas is generated inside the battery due to an overcharged state, the spacer plate There is a problem that the outflow of gas is hindered by the shaped part and the safety valve does not function at the set pressure.

According to the present invention, a spacer for fixing an electrode group is provided in a sealed battery, and a mesh-shaped through portion is provided on a surface where the spacer and the electrode group are in contact with each other, so that an electrolyte to be injected into the battery is wound. The non-aqueous electrolyte spreads over all of the positive electrode layer and the negative electrode layer in the electrode group, and the non-aqueous electrolyte solution is uniformly impregnated inside the electrode group from the top and bottom in the height direction of the electrode group to the center of the electrode group. . In addition, when gas is generated inside the battery due to overcharge, etc., the battery can be removed from the safety valve without obstructing the flow of gas flowing out from the electrode group to the safety valve by providing a mesh-like through portion on the surface where the spacer and the electrode group contact. It can be discharged to the outside. As a result, it is possible to provide a sealed battery that is excellent in charge / discharge characteristics, cycle characteristics, and the like, and that has high safety and reliability.

The sealed battery according to the present invention includes an outer can, an electrode group that is housed in the outer can and includes a positive electrode and a negative electrode, a battery sealing body that is attached to an opening of the outer can, and the battery sealing body or the outer packaging. A sealed battery comprising a safety valve provided on a can and a spacer disposed at a position in contact with the electrode group,
The spacer has a flat portion on a surface in contact with the electrode group, and the flat portion forms a plurality of through passages.

The present invention provides an electrode in which an electrolyte to be injected into the battery is wound by arranging a spacer inside the sealed battery and forming a plurality of through passages in a plane portion of a surface in contact with the electrode group of the spacer. The non-aqueous electrolyte is spread all over the positive electrode layer and the negative electrode layer in the group, and the non-aqueous electrolyte is uniformly impregnated into the electrode group from the upper and lower parts in the height direction of the electrode group to the center part of the electrode group. A highly safe sealed battery with excellent battery characteristics that can be discharged from the safety valve to the outside of the battery without obstructing the flow of gas flowing out from the electrode group to the safety valve when gas is generated inside the battery due to overcharging, etc. Can be provided.

The expanded view which shows the sealed battery of embodiment. The figure which shows the spacer of embodiment.

Hereinafter, a sealed battery according to an embodiment of the present invention will be described with reference to the drawings.

The square sealed battery shown in FIG. 1 includes an outer can 1 having a bottomed rectangular cylindrical shape. The outer can 1 is
For example, it is formed by subjecting an aluminum plate or an aluminum alloy plate to deep drawing. The electrode group 2 is formed by, for example, winding a sheet-like positive electrode and a sheet-like negative electrode in a spiral shape with a separator in between, and then crushing the whole into a square shape that matches the cross-sectional shape of the battery can It is produced by doing.

The positive electrode is produced, for example, by applying a slurry containing a positive electrode active material to a current collector made of an aluminum foil or an aluminum alloy foil. As the positive electrode active material, oxides, sulfides, polymers, and the like that can occlude and release lithium can be used. Preferable active materials include lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium iron phosphate, and the like that can obtain a high positive electrode potential. The negative electrode is produced by applying a slurry containing a negative electrode active material to a current collector made of an aluminum foil or an aluminum alloy foil. As the negative electrode active material, metal oxides, metal sulfides, metal nitrides, alloys, and the like that can occlude and release lithium can be used. Preferably, the occlusion and release potential of lithium ions is 0.4 V or higher relative to the metal lithium potential. It is a substance. Since the negative electrode active material having such a lithium ion storage / release potential can suppress the alloy reaction between aluminum or an aluminum alloy and lithium, it is possible to use aluminum or an aluminum alloy for a negative electrode current collector and a negative electrode related component. And For example, there are titanium oxide, lithium titanium oxide, tungsten oxide, amorphous tin oxide, tin silicon oxide, silicon oxide, etc. Among them, lithium titanium composite oxide is preferable. As the separator, a microporous film, a woven fabric, a non-woven fabric, a laminate of the same material or different materials among these can be used. Examples of the material for forming the separator include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-butene copolymer.

A non-aqueous electrolyte (not shown) is accommodated in the outer can 1 and impregnated in the electrode group 2.

The non-aqueous electrolyte is prepared by dissolving an electrolyte (for example, a lithium salt) in a non-aqueous solvent. Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (γ -BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like. Nonaqueous solvents may be used alone or in combination of two or more. Examples of the electrolyte include lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenide (LiAsF6), and lithium trifluoromethanesulfonate (LiCF3SO).
3) etc. can be mentioned. The electrolyte may be used alone or in combination of two or more. The amount of electrolyte dissolved in the non-aqueous solvent is 0.2 mol / L to 3 mol /.
L is desirable.

As shown in FIG. 1, the plurality of positive electrode conductive tabs 3 are electrically connected to a plurality of locations of the positive electrode, and each is led upward from the upper end face of the electrode group 2. On the other hand, the plurality of negative electrode conductive tabs 4 are electrically connected to a plurality of portions of the negative electrode, and each is led upward from the upper end face of the electrode group 2. As the positive electrode conductive tab 3, for example, a positive electrode current collector partially extended can be used, but may be separate from the positive electrode. Moreover, for the negative electrode conductive tab 4, for example, a negative electrode current collector partially extended can be used.
It may be a separate body from the negative electrode.

The positive electrode conductive tab 3 is covered with a positive electrode protection lead 5 in which the outermost layers of both of the overlapped portions are U-shaped or folded in two after at least the tip portions are overlapped. The positive electrode protection lead 5 is fixed to the positive electrode conductive tab 3 by welding. On the other hand, the negative electrode conductive tab 4 is covered with a negative electrode protective lead 6 in which at least the front end portions are overlapped, and the outermost layers of both of the overlapped portions are U-shaped or folded in two. The negative electrode protection lead 6 is fixed to the negative electrode conductive tab 4 by welding. In addition, although methods, such as laser welding, ultrasonic welding, resistance welding, are used for the welding method of a conductive tab and a protection lead, ultrasonic welding is preferable. The material of the positive electrode protection lead 5 can be, for example, aluminum or an aluminum alloy. The material of the negative electrode protection lead 6 can be aluminum or an aluminum alloy, for example. The material of the positive electrode protection lead 5 is the positive electrode conductive tab 3.
The negative electrode protection lead 6 is preferably the same material as the negative electrode conductive tab 4.

A square plate-like positive electrode intermediate lead 7 is welded to one surface outside the positive electrode protection lead 5. The positive intermediate lead 7 is desirably larger in size than the area facing the positive electrode protection lead 5, and the thickness is desirably small from the thickness of the positive electrode lead 15. A rectangular plate-like negative electrode intermediate lead 8 is welded to one surface outside the negative electrode protection lead 6. The negative electrode intermediate lead 8 is desirably larger in size than the area facing the negative electrode protection lead 6, and the thickness is desirably small with respect to the thickness of the negative electrode lead 14. As a welding method, laser welding, ultrasonic welding, resistance welding, or the like is used, but ultrasonic welding is preferable. The material of the positive electrode intermediate lead 7 can be, for example, aluminum or an aluminum alloy. The material of the negative electrode intermediate lead 8 can be, for example, aluminum or an aluminum alloy. The material of the positive electrode intermediate lead 7 is preferably the same material as that of the positive electrode conductive tab 3, and the material of the negative electrode intermediate lead 8 is preferably the same material as that of the negative electrode conductive tab 4.

The opening of the outer can 1 is sealed with a sealing member 9. As shown in FIG. 1, the sealing member 9 includes a battery sealing body 10 that closes the opening of the outer can 1, and an output terminal (rivet) 12 that is attached to the outer surface (upper surface) of the battery sealing body 10 via a gasket 11. And the inner surface of the battery sealing body 10 (
A negative electrode lead 14 and a positive electrode lead 15 attached to the lower surface via an insulator 13. Examples of the material of the gasket 11 include polypropylene (PP) and thermoplastic fluororesin. Examples of the thermoplastic fluororesin include tetrafluoroethylene-
Examples thereof include perfluoroalkoxyethylene copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

The battery sealing body 10 is made of a press-molded product made of aluminum or an aluminum alloy plate material. A through hole 16 is formed on the plate surface for mounting the gasket 11. A receiving seat 17 for the gasket 11 is formed in a recess. Receiving seat 1
Reference numeral 7 denotes a shape other than a circle for stopping rotation, for example, a quadrangle in FIG. On the other hand, the positive electrode terminal 18 as the electrode terminal protrudes in a convex shape on the upper surface side of the battery sealing body 10. Positive terminal 1
The front end face 8 has a shape other than a circle for preventing rotation, for example, a quadrangle in FIG. The pressure release valve includes an X-shaped groove 19 provided on the bottom surface in the recess located between the receiving seat 17 and the positive electrode terminal 18 on the upper surface of the battery sealing body 10, and the case internal pressure is constant. If it exceeds, the groove 19 breaks to release the internal pressure. The electrolyte solution injection port 20 is formed after the electrolyte solution is injected.
It is closed with a sealing plug 21. The sealing plug 21 is welded to the battery sealing body 10.

The negative electrode lead 14 is provided so as to communicate with the shaft through hole 30 of the insulator 13, and at least a part of the first plate portion 14 a having a shaft through hole 14 c having a shape other than a circular shape,
And a second plate portion 14b extending from the plate portion 14a to the electrode group 2 side, and has an L-shaped cross-sectional shape. The first plate portion and the second plate portion are made of a conductive material. The shaft through hole 14c is a circular hole. The shaft tip 24 of the output terminal 12 is inserted into the shaft through hole 14c. The thickness of the negative electrode lead 14 is desirably 0.5 to 1.5 mm. The material of the negative electrode lead 14 is changed according to the material of the active material. When the negative electrode active material is lithium titanate, aluminum or an aluminum alloy can be used.

The positive electrode lead 15 includes a first plate portion 15 a made of a rectangular plate and a first plate portion 1.
A second plate portion 15b extending from 5a to the electrode group 2 side. The first plate portion and the second plate portion are made of a conductive material. Laser welding is performed around the positive electrode terminal 18 in contact with the first plate portion 15 a and the lower surface of the battery sealing body 10. Although the material of the positive electrode lead 15 is changed depending on the type of the positive electrode active material, for example, aluminum or an aluminum alloy can be used.

On the second plate portion 14b of the negative electrode lead 14 of the sealing member 9, as shown in FIGS.
The negative intermediate lead 8 is laser welded, and the positive intermediate lead 7 is laser welded to the second plate portion 15 b of the positive lead 15 of the sealing member 9. Providing the positive and negative intermediate leads 7 and 8 facilitates electrical connection between the sealing member 9 and the positive and negative electrode conductive tabs 3 and 4 of the electrode group 2. That is, the positive and negative electrode conductive tabs 3 and 4 are sandwiched between the positive and negative electrode protective leads 5 and 6 and the intermediate leads 7 and 8, and these are integrated by ultrasonic welding, and then the intermediate leads 7 and 8 are connected to the positive and negative electrode leads 14 and 1 respectively.
By performing laser welding on the sealing member 5, vibration is not applied to the sealing member 9 during welding, so that the breakage of the groove 19 of the pressure release valve provided in the sealing member 9 can be prevented. When the protective lead can be thickened and the conductive tab to which the protective lead is welded can be laser-welded to the lead member, the intermediate lead may not be used.

After the electrical connection between the sealing member and the electrode group, the various positive electrode leads and the various negative electrode leads connecting the sealing member and the electrode group are arranged so as to be sandwiched between the spacers 41a and 41b, and the electrode in the battery can 1 They are arranged in a space provided between the upper end surface 2 a of the group 2 and the lower surface of the lid 10. And after fitting the battery sealing body 10 in the exterior can 1, the fitting surface of the battery sealing body 10 and the exterior can 1 is sealed by welding. Finally, after injecting the electrolyte into the outer can 1 from the electrolyte inlet 20 of the battery sealing body 10, a sealing plug 21 is fitted into the inlet 20 and welded. The battery shown in FIG. 1 is obtained by sealing.

The spacer is shown in FIG. 1 and FIG. The spacers 41 a and 41 b are arranged in a space provided between the upper end surface 2 a of the electrode group 2 and the lower surface of the battery sealing body 10 in the battery can 1. The spacer 41a is provided with partition plates 42a to 42c at both short sides of the rectangular plate and an intermediate point in the long side direction. Concave portions 43 are provided on the end surfaces of the partition plates 42a to 42c. A pressing plate in which through passages 46a to 46c are formed at positions facing the upper end surface 2a of the electrode group 2 in a form connected to the partition plates 42a to 42c. On the other hand, the spacer 41b is provided with partition plates 44a to 44c at both short sides of the rectangular plate and an intermediate point in the long side direction. On the end faces of the partition plates 44a to 44c, projections 45 for fitting into the recesses 43 of the spacer 41a are provided. Partition plates 44a-4
A pressing plate (not shown) in which a through path is formed at a position facing the upper end surface 2a of the electrode group 2 in a form connected to 4c. Projection 45 of partition plates 44a-44c of spacer 41b
Is inserted into the recess 43 of the partition plates 42a to 42c of the spacer 41a, the spacer 41a
The positive electrode conductive tab 3 and the positive electrode lead 15 are located in a space surrounded by the partition plates 42a and 42b and the partition plates 44a and 44b of the spacer 41b, and the partition plates 42b and 4 of the spacer 41a.
The negative electrode conductive tab 4 and the negative electrode lead 14 are located in a space surrounded by 2c and the partition plates 44b and 44c of the spacer 41b. Thereby, the insulation between the positive electrode conductive tab 3 and the negative electrode conductive tab 4,
Insulation between the positive electrode lead 15 and the negative electrode lead 14 and insulation between these members and the battery can 1 are achieved. Holes can be provided in the four corners of the spacers 41a and 41b in order to more impregnate the gap between the battery can 1 and the electrode group 2 with the electrolytic solution.

The spacers 41a and 41b can prevent the electrode group 2 from moving when vibrations or impacts are applied to the battery. Furthermore, since the electrolyte injected from the electrolyte injection port 20 accumulates in the upper part of the electrode group 2, the electrolyte is easily impregnated from the upper end surface of the electrode group 2, and the electrode group 2 is uniformly impregnated with the electrolyte. be able to. As a material of the spacers 41a and 41b, polypropylene (
PP), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS)
) And tetrafluoroethylene-hexafluoropropylene copolymer (PFA).

Example 1
The outer can 1 is formed by drawing an aluminum plate 20 mm long, 100 mm wide, and 110 mm high.
A rectangular outer can having a can wall thickness of 0.5 mm was used. Next, a positive electrode plate prepared by applying LiCoO2 as a main active material to a strip-shaped current collector as a positive electrode and Li4 + xTi5O12 (x is -1≤)
An electrode group 2 is formed in which a negative electrode plate formed by applying lithium titanate having a spinel structure represented by x ≦ 3) to a strip-shaped current collector as a main active material is wound with a separator interposed therebetween. Group 2
The positive electrode tab 3 and the positive electrode terminal 18 extending from each other are welded via the positive electrode protection lead 5, the positive electrode intermediate lead 7 and the positive electrode lead 15. Similarly, one negative electrode tab 4 and the negative electrode terminal 12 are connected to the negative electrode protection lead 6. After welding through the negative electrode intermediate lead 8 and the negative electrode lead 14, the positive electrode conductive tab 3 and the positive electrode lead 15 are placed in a space surrounded by the partition plates 42a and 42b of the spacer 41a and the partition plates 44a and 44b of the spacer 41b. The negative electrode conductive tab 4 and the negative electrode lead 14 are positioned in a space surrounded by the partition plates 42b and 42c of the spacer 41a and the partition plates 44b and 44c of the spacer 41b. Thereby, the insulation between the positive electrode conductive tab 3 and the negative electrode conductive tab 4, the insulation between the positive electrode lead 15 and the negative electrode lead 14, and the insulation between these members and the battery can 1 are achieved. Then, the electrode group 2 was inserted into the outer can 1, the battery sealing body 10 was fitted into the outer can opening, and the fitting portion was integrated by laser welding.

As a non-aqueous electrolyte, lithium salt LiBF4 is mixed with an organic solvent in which ethylene carbonate (EC) and γ-butyrolactone (GBL) are mixed at a volume ratio (EC: GBL) of 1: 2.
Is dissolved at 1.5 mol / L to prepare a liquid non-aqueous electrolyte (non-aqueous electrolyte), the battery semi-product obtained as described above is placed under reduced pressure, and this non-aqueous electrolyte is added to the electrolyte injection port 20. After more liquid injection
After closing the liquid injection port with the sealing plug 21, the battery sealing body 10 is laser welded around the sealing plug 21.
Is welded to 20mm in length, 100mm in width, 110mm in height, and a capacity of 6000m.
1000 Ah sealed rectangular lithium ion secondary batteries were produced.

As shown in FIG. 2, spacers 41a and 41b are 11 mm long and 6 mm wide as shown in FIG.
A plurality of through-passages having a length of 0 mm and a height of 10 mm and a side of 0.5 mm were provided in the pressing plates 46a to 46c.

(Example 2)
The spacers 41a and 41b are 11 mm in length, 60 mm in width, and 10 mm in height.
1000 sealed batteries having the same configuration as in Example 1 were prepared except that a plurality of through passages each having a side of 1 mm were provided on 46c.

(Example 3)
The spacers 41a and 41b are 11 mm in length, 60 mm in width, and 10 mm in height.
One thousand sealed batteries having the same configuration as in Example 1 were prepared except that a plurality of through passages each having a side of 4 mm were provided in 46c.

(Comparative Example 1)
The spacers 41a and 41b are 11 mm in length, 60 mm in width, and 10 mm in height.
A sealed battery having the same configuration as in Example 1 except that no through passage is provided in 46c is 1000.
Individually produced.

The sealed batteries produced in the above Examples and Comparative Examples were subjected to vibration tests and impact tests in accordance with the UN Recommendations on the Transport of Dangerous Goods (UN No. 3090). The vibration test is a test in accordance with the UN Recommendation on Regulations on the Transport of Dangerous Goods (UN No. 3090).
From 200 Hz to 200 Hz, and continuously from 200 Hz to 7 Hz in a total of 15 minutes, the sweep is performed as one set 12 times in three directions of the battery height direction, width direction, and thickness direction. In the impact test, a half-sine impact with a peak acceleration of 150G and a pulse duration of 6 milliseconds was applied to each of the three directions of the battery in the height direction, width direction, and thickness direction, that is, each of the six surfaces of the battery. Is a test in which three impacts are given to a battery and a total of 18 impacts are given to one battery.

A vibration test and an impact test were performed, and after the test, the battery was disassembled to confirm the damage condition of the electrode group. The damage to the electrode group is due to the movement of the electrode group within the battery. Bending occurs, and further, the end of the electrode is cut. Moreover, the cutting | disconnection, disconnection, etc. in the conductive connection part of the tab of an electrode group or an electrode group and a battery sealing body were observed and confirmed.

Furthermore, an overcharge test was performed under the condition of 10C-12V to test the safety of the battery. In the overcharge test, when the current value that can fully charge the battery in 1 hour is 1C, 10C current that is 10 times that current is passed through the battery, and the maximum value of the power supply voltage is set to 12V. To do.

In addition, in order to evaluate the impregnation property of the electrolyte solution into the electrode group, the assembled battery is disassembled, the impregnation state of the electrolyte solution into the electrode, and further the battery characteristics are evaluated by a cycle test. The impregnation property was confirmed. Regarding the state of impregnation of the electrolyte into the electrode, the battery was disassembled after the battery was assembled, and the state of impregnation of the electrolyte into the electrode was confirmed. The impregnation state is confirmed by checking whether the active material layer applied on the surface of the electrode is wetted by the electrolytic solution, and the surface is wet ◎, only the edge of the electrode is wet and the center is not wet (electrode The evaluation was evaluated as Δ, where there was a portion that was not wet within a range of 50% or less of the area. The test was conducted using 100 batteries for each test content. The results of these evaluations are shown in Table 1.

As is clear from Table 1, the UN Recommendation on Regulations on the Transport of Dangerous Goods (UN No. 3090)
Vibration test and peak acceleration 150G, pulse duration 6ms sine half wave (half-s
ine) As a result of the impact test that gives an impact, the battery of the example has a flat portion on the surface in contact with the electrode group of the spacer disposed in the battery, and the flat portion forms a plurality of through passages. When conducting a vibration test or impact test, the electrode group that is about to move in the battery due to vibration or impact is flexibly pressed down, so that the conductive connection between the electrode group tab or electrode group and the battery sealant There is no damage such as cuts and disconnections. This is because the presser plate portion has flexibility by forming a through-passage in the presser plate of the spacer, and the vibration and impact to the electrode group are reduced. On the other hand, in the comparative example, since there is no through path in the spacer pressing plate, the electrode group in the battery is directly affected by the spacer pressing plate due to vibration or impact, and the electrode group is damaged.

Next, an overcharge test was performed on the assembled battery. When the battery is overcharged, the non-aqueous solvent in the non-aqueous electrolyte is decomposed, gas is generated inside the battery, the battery internal pressure is increased, and at the same time, the battery temperature is increased. Therefore, when the internal pressure of the battery rises above a certain level, the safety valve that discharges the generated gas to the outside of the battery is activated to discharge the gas to the outside of the battery, and the battery temperature is prevented from rising to ensure the safety of the battery. To do. In the battery of the example, when an overcharge test was performed, gas discharge from the safety valve was observed after a while. Moreover, when the temperature of the battery under test was measured, it was increased to 117 ° C. at the maximum. After gas was discharged from the safety valve, the battery temperature began to gradually drop, confirming that safety was ensured. This is because a sufficient gas outflow path is secured. In other words, since a through passage is formed in the holding plate of the spacer in the battery, the gas generated in the electrode group passes through the through passage of the spacer from the electrode group and efficiently passes to the safety valve arranged in the battery sealing body. This is because gas was discharged from the safety valve.

On the other hand, in the comparative example, the gas generated in the electrode group is pressed on the upper end surface of the electrode group by a pressing plate provided in the spacer, so that the electrode group provided in the spacer and the battery sealing body Since the gas flows from the notch that houses the conductive member connecting to the safety valve, the gas outflow path is limited, and the gas generated in the electrode group cannot be efficiently guided to the safety valve. For this reason, it takes a long time from the start of the overcharge test until the gas is discharged from the safety valve as compared with the embodiment. Furthermore, when the battery temperature during the test was measured, the maximum was 243 ° C.
It was confirmed that it was rising.

Next, evaluation on the impregnation property of the electrolytic solution into the electrode group was performed. Injecting the electrolyte into the battery, the nonaqueous electrolyte is spread over all of the positive electrode layer and the negative electrode layer in the electrode group in which the injected electrolyte solution is wound,
It is desirable that the non-aqueous electrolyte is uniformly impregnated into the electrode group from the upper and lower portions in the height direction of the electrode group to the center of the electrode group. Therefore, after assembling the batteries of the examples and comparative examples, the batteries were disassembled and the state of impregnation of the electrolyte into the electrodes was confirmed. The impregnation state can be confirmed by whether or not the active material layer applied to the surface of the electrode is wetted by the electrolytic solution. In addition, the assembled battery is cycle tested 1C.
-2.8V CCCV charge and 1C-1.8V CC discharge were performed, and the number of cycles was evaluated.

When the battery of the example was disassembled and the surface of the electrode was observed, it was confirmed that the entire surface was wet with the electrolyte. In the battery of the comparative example, it was confirmed that the end portion of the electrode was wet, but the electrolyte solution was not wet in the center portion of the electrode, and it was not possible to confirm that the electrolyte solution was impregnated.

Next, when a cycle test was performed, the batteries of the examples had 8000 cycles or more for all the batteries, whereas the batteries of the comparative example had a maximum of 5469 cycles. In the battery of the embodiment, a spacer for fixing the electrode group is provided, and a mesh-shaped through portion is provided on a surface where the spacer and the electrode group are in contact with each other, so that an electrolyte solution to be injected into the battery is wound. The non-aqueous electrolyte is spread all over the positive electrode layer and the negative electrode layer in the group, and the non-aqueous electrolyte is uniformly impregnated inside the electrode group from the upper and lower parts in the height direction of the electrode group to the central part of the electrode group.

As described above, in the present invention, a spacer for fixing an electrode group is provided in a sealed battery, and a mesh-like through portion is provided on a surface where the spacer and the electrode group are in contact with each other. The electrode group to be worked can be pressed with flexibility, and there is no damage such as disconnection or disconnection at the tab of the electrode group or at the conductive connection portion between the electrode group and the battery sealing member. In addition, when the electrolyte is injected from the injection port of the battery sealing body and injected into the electrode group, the electrode is uniformly injected from the through-hole of the spacer onto the upper surface of the electrode group, and the electrolyte is wound. The non-aqueous electrolyte spreads over all of the positive electrode layer and the negative electrode layer in the group, and the non-aqueous electrolyte is uniformly impregnated into the inside of the electrode group from the top and bottom in the height direction of the electrode group to the center of the electrode group. In addition, when gas is generated inside the battery due to overcharge, etc., the battery can be removed from the safety valve without obstructing the flow of gas flowing out from the electrode group to the safety valve by providing a mesh-like through portion on the surface where the spacer and the electrode group contact. It can be discharged to the outside. Thereby, it is excellent in charging / discharging characteristics, cycle characteristics, etc., and safety and reliability can be secured.

In other words, the sealed battery according to the present invention is provided with a spacer for fixing the electrode group, and a mesh-shaped through portion is provided on the surface where the spacer and the electrode group are in contact with each other. Can provide a sealed battery with excellent characteristics and cycle characteristics, and is particularly suitable as an in-vehicle secondary battery mounted on a hybrid vehicle or an electric vehicle, or a secondary battery for power storage used for power leveling. .

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Exterior can, 2 ... Electrode group, 3 ... Positive electrode conductive tab, 4 ... Negative electrode conductive tab, 5 ... Positive electrode protection lead,
6 ... Negative electrode protective lead, 7 ... Positive electrode intermediate lead, 8 ... Negative electrode intermediate lead, 9 ... Sealing member, 10 ...
Battery sealing body, 11 ... gasket, 12 ... output terminal, 13 ... insulator, 14 ... negative electrode lead, 1
5 ... Positive electrode lead, 16 ... Through hole, 17 ... Receiving seat, 18 ... Positive electrode terminal, 19 ... Pressure release valve, 2
0 ... Electrolyte injection port, 41a, 41b ... Spacer, 46a, 46b1, 46b2, 46c ...
Holding plate

Claims (2)

An outer can, an electrode group housed in the outer can and including a positive electrode and a negative electrode, a battery sealing body attached to an opening of the outer can, a safety valve provided on the battery sealing body or the outer can, and the A sealed battery comprising a spacer disposed at a position in contact with an electrode group,
The spacer has a flat portion on a surface in contact with the electrode group, and the flat portion forms a plurality of through passages. One side of the through-passage of the flat portion formed on the surface in contact with the electrode group of the spacer is 0.5 mm to 4 m.
The sealed battery according to claim 1, wherein m is m.

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