JP2013077465A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery having excellent impact resistance and vibration resistance.SOLUTION: A battery 1 includes: a power generation element 8 formed by laminating or winding a positive electrode plate 19A and a negative electrode plate 19B through a separator; an electrolyte; and a case 2 housing the power generation element 8 in a state of being immersed in the electrolyte. The present invention is characterized by disposing a buffer material 10 made of material which expands with the electrolyte, between the power generation element 8 and an inner wall 2A of the case 2. By disposing the buffer material 10, the battery 1 having excellent impact resistance and vibration resistance can be provided.

Description

  The present invention relates to a battery.

Conventionally, as a battery including a power generation element formed by laminating or winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, an electrolytic solution, and a case in which the power generation element is immersed in the electrolytic solution, for example, a patent The battery described in Document 1 is known.
In this battery, the positive electrode plate is extended to the side of the battery and bonded to the positive electrode current collector, and the negative electrode plate is extended to the opposite side and bonded to the negative electrode current collector. Soaked in

JP 2011-14276 A

  In the battery of Patent Document 1, as shown in FIG. 3 of Patent Document 1, since there is a gap between the case and the power generation element, the power generation element may move due to impact or vibration of the battery. is there. In this way, when the power generation element moves and collides with the inner wall of the case, the resistance between the electrode plate and the current collector is broken, the electrode plate is damaged or deformed, and the active material falls off the electrode plate. There are concerns about the rise and the occurrence of internal short circuits.

  The present invention has been completed based on the above circumstances, and an object thereof is to provide a battery excellent in impact resistance and vibration resistance.

  In order to solve the above problems, the present invention accommodates a power generation element in which a positive electrode plate and a negative electrode plate are laminated or wound with a separator interposed therebetween, an electrolytic solution, and the power generation element immersed in the electrolytic solution. A shock absorber made of a material that is expanded by the electrolyte solution between the power generation element and the inner wall of the case.

In the present invention, for example, a buffer material is attached to a position facing the inner wall of the case on the outer surface of the power generation element, and then accommodated in the case. Located between the element and the inner wall of the case. The power generation element is held in a state of being spaced from the inner wall of the case by the cushioning material arranged in this way, and even if the battery receives impact or vibration, the electrode plate and the current collector Problems such as breakage of the joints and breakage of the electrode plate are less likely to occur.
As a result, according to the present invention, a battery excellent in impact resistance and vibration resistance can be provided.

  In addition, since the cushioning material used in the present invention expands after being immersed in the electrolyte in the case, the volume before being accommodated in the case is smaller than the volume after being expanded in the case. State. That is, since the volume of the cushioning material is smaller than the volume of the cushioning material accommodation space in the case when the work is accommodated in the case, the work of accommodating the cushioning material in the case can be performed smoothly. it can.

The present invention may have the following configuration.
The buffer material may be disposed between an end face of the power generation element and an inner wall of the case.

In the case, the power generation element absorbs the electrolyte in the stacking direction of the electrode plates or in the winding direction of the electrode plate and expands. The outer peripheral surface of the element is in contact with the case inner wall, and the problem of collision between the power generation element and the case inner wall is less likely to occur.
However, the power generation element is accommodated in the case because it is difficult to expand in the direction perpendicular to the stacking direction of the electrode plates and the direction perpendicular to the winding direction (winding axis direction) even when the electrolyte is absorbed. Even after the electrolyte is injected into the power generation element, a gap is left between the end face of the power generation element (the face on which the end face of the electrode plate is disposed) and the inner wall of the case. Therefore, with the configuration as described above, the buffer material is disposed between the surface of the power generation element that is not easily expanded and the inner wall surface of the case, so even if the battery is subjected to shock or vibration, The impact of shock and vibration can be reliably mitigated by the cushioning material.

At least one of the positive electrode plate and the negative electrode plate has an active material uncoated portion where an active material is not applied to an end portion, the active material uncoated portion is disposed at an end portion of the power generation element, and the buffer The material may be arranged so as to cover the end face of the power generation element and the active material uncoated portion.
Even if there is no space between the case and the case where the active material is applied, a space may be formed between the case and the uncoated part where the active material is not applied. With such a configuration, since the cushioning material is also disposed in such a space, it is excellent in impact resistance and vibration resistance.

The buffer material may be composed of polyvinylidene fluoride or a mixed resin of polyvinylidene fluoride and polystyrene.
Such a configuration is preferable because the buffer material easily expands in the non-aqueous electrolyte used in the lithium ion secondary battery.

  According to the present invention, a battery excellent in impact resistance and vibration resistance can be provided.

Partial cross-sectional view schematically showing the battery of Embodiment 1. The perspective view which showed the electric power generation element before accommodating in a case

<Embodiment 1>
A first embodiment in which the present invention is applied to a lithium ion battery 1 will be described with reference to FIGS.
As shown in FIG. 1, the battery 1 of the present embodiment includes a power generation element 8 and an electrolyte solution (not shown) in a substantially rectangular parallelepiped case 2 opened upward.

  A flat lid 3 is attached to the opening 2B of the case 2 so as to close the opening 2B. The lid 3 is made of a metal material and has a rectangular shape corresponding to the opening 2B of the case 2 as shown in FIGS. Two electrode terminals 4A and 4B (a positive terminal 4A and a negative terminal 4B) are attached to the upper surface of the lid 3 in a state of being supported by a resin support part 5, and the two electrode terminals 4A and 4B A liquid injection port 6 for injecting an electrolytic solution into the case 2 is provided therebetween.

  As shown in FIG. 2, each electrode terminal 4A, 4B is substantially U-shaped, and a bus bar for electrically connecting to the electrode terminal 4 of an adjacent battery (not shown) is provided at the tip thereof. Etc. can be attached.

  The electrode terminals 4A and 4B are connected to current collectors 7A and 7B that pass through the lid portion 3 and the support portion 5 and are arranged in the case 2. That is, in this embodiment, the positive electrode terminal 4A is formed integrally with the positive electrode current collector 7A, and the negative electrode terminal 4B is formed integrally with the negative electrode current collector 7B. In the present embodiment, the electrode terminal 4A and the current collector 7A arranged on the left side in FIG. 1 are defined as the positive electrode terminal 4A and the positive electrode current collector 7A, respectively, and the electrode terminal 4B and the current collector 7B arranged on the right side in the drawing are used. Are a negative electrode terminal 4B and a negative electrode current collector 7B, respectively. The electrode terminal 4 is used when the positive terminal 4A and the negative terminal 4B are summarized, and the current collector 7 is used when the positive current collector 7A and the negative current collector 7B are summarized.

  The positive electrode current collector 7A and the positive electrode terminal 4A are made of a metal material such as aluminum, and the negative electrode current collector 7B and the negative electrode terminal 4B are made of a metal material such as copper. The current collector 7 and the electrode terminal 4 are formed by punching a metal plate into a predetermined shape or cutting it into a predetermined shape, and then bending the current collector 7 and the electrode terminal 4 into the shape shown in FIG. can get.

  A member integrally including the current collector 7 and the electrode terminal 4 can be attached to the lid 3 by, for example, metal-resin bonding. This metal-resin bonding is a technique for firmly bonding a metal and a resin. For example, the surface of the metal is surface-treated to form a minute recess, and the surface-treated metal is placed in a mold to form a resin. Injection molding. Specifically, after the above-described surface treatment is performed on the member integrally including the current collector 7 and the electrode terminal 4 and the lid 3, the electrode terminal 4 is inserted into a hole (not shown) in the lid 3. ) And placed in the mold in the posture shown in FIG. And the lid | cover part 3 to which the electrode terminal 4 of the structure shown in FIG. 2 was attached is obtained by injection-molding resin to the said metal mold | die.

  Inside the case 2, the power generation element 8 and the current collector 7 are accommodated in a state immersed in an electrolytic solution. The power generation element 8 is formed by winding a strip-shaped positive electrode plate 19A and a strip-shaped negative electrode plate 19B via a separator (not shown). Although not shown in detail, a positive electrode active material is applied to the positive electrode plate 19A, and a negative electrode active material is applied to the negative electrode plate 19B. As shown in FIG. 1, the positive electrode plate 19A extends to the left side in the drawing, and the extended end is an active material uncoated portion 9A (a strip-shaped portion shown in the drawing) where no positive electrode active material is applied, and the positive electrode current collector 7A Are joined by welding. As shown in FIG. 1, the negative electrode plate 19B extends to the right side in the figure, and its extended end is an active material uncoated portion 9B (a strip-shaped portion shown in the figure) where no negative electrode active material is applied, and the negative electrode current collector 7B Are joined by welding.

  As the positive electrode plate 19A, for example, a metal foil such as an aluminum foil can be used. As the positive electrode active material, a known material as a positive electrode active material of a lithium ion battery such as a lithium composite oxide containing lithium or manganese is used. be able to.

  As the negative electrode plate 19B, for example, a metal foil such as a copper foil can be used. As the negative electrode active material, lithium metal, a lithium-aluminum alloy, a lithium-lead alloy, and a lithium that can absorb and release lithium are used. -A well-known negative electrode active material of a lithium ion battery, such as a lithium alloy such as a tin alloy, graphite, coke, an organic fired body, and a carbon material such as amorphous carbon can be used.

As the electrolytic solution, a known one can be used as an electrolytic solution (non-aqueous electrolytic solution) for a lithium ion battery.

  Specific examples of the non-aqueous solvent for the non-aqueous electrolyte include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate, chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, γ-butyrolactone, cyclic esters such as γ-valerolactone, chain esters such as methyl acetate and methyl propionate, cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran and tetrahydropyran, chain ethers such as dimethoxyethane and dimethoxymethane, Cyclic phosphate esters such as ethylene methyl phosphate and ethyl ethylene phosphate, chain phosphate esters such as trimethyl phosphate and triethyl phosphate, halides of these compounds, and the like can be used. Only one kind of these organic solvents may be selected and used, or two or more kinds may be used in combination.

As a solute of the non-aqueous electrolyte, inorganic lithium salts such as LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN Fluorine-containing organic lithium salts such as (CF ₃ CO) and LiC (CF ₃ SO ₂ ) ₃ can be mentioned. Only one type of these solutes may be selected and used, or two or more types may be used in combination.

  As a separator, a well-known thing can be used as a separator of a lithium ion battery, such as a polyethylene microporous membrane, for example.

In the present embodiment, the power generation element 8 is arranged in a state in which the end faces of the electrode plates 19A and 19B are arranged on the left and right shown in FIG. Between the left end face 8A of the power generation element 8 where the end faces of the electrode plates 19A and 19B are arranged and the inner wall 2A of the case 2, and between the right end face 8A of the power generation element 8 and the inner wall 2A of the case 2, respectively. A buffer material 10 made of a material that is expanded by the electrolytic solution is disposed.
In the present embodiment, the cushioning material 10 is disposed so as to cover the left end surface 8A and the active material uncoated portion 9A at the left end portion of the power generation element 8 in FIG. 1, and the right end portion of the power generation element 8 in FIG. Then, it arrange | positions so that 8 A of right sides and the active material non-application part 9B may be covered.

The buffer material 10 may be any material as long as it is made of a material that expands with an electrolytic solution, and the shape may be a sheet shape or a fiber shape. Specific examples of the material of the buffer material 10 include resins such as acrylonitrile resin, methyl methacrylate resin, polyvinylidene fluoride resin, polyethylene oxide resin, polysulfone resin, epoxy resin, carboxymethyl cellulose resin, and the like. Examples thereof include the above-mentioned resins having a crosslinked structure, polytetrafluoroethylene, polyimide resins, polyolefin resins, polystyrene resins and the like. These materials can be used alone or in combination of two or more.
Among these materials, polyvinylidene fluoride or a mixed resin of polyvinylidene fluoride and polystyrene is preferable because it easily expands in a non-aqueous electrolyte used as an electrolyte for a lithium ion battery.

  Examples of the material of the buffer material 10 include one or more fibers selected from polyester fibers, acrylic fibers, polyamide fibers, polyvinyl fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, cellulose fibers, and the like. May be mixed. Mixing these fibers is preferable because the cushioning material 10 is more likely to swell.

  When the cushioning material 10 is disposed, the cushioning material 10 is placed on the outer surface of the power generation element 8 at a position facing the inner wall 2A of the case 2 (the end surface 8A of the power generation element 8 in this embodiment), for example, with an adhesive or It is inserted into the case 2 in a state where it is stuck with an adhesive tape or the like. When the electrolytic solution is injected after the power generation element 8 with the buffer material 10 attached is accommodated in the case 2, the buffer material 10 expands due to the electrolytic solution, and between the inner wall 2 </ b> A of the case 2 and the end face 8 </ b> A of the power generation element 8. Placed in. In this way, the battery 1 of the present embodiment is obtained.

  In the battery 1 of this embodiment, the power generation element 8 absorbs the electrolyte and expands in the winding direction of the electrode plates 19A and 19B due to the injection of the electrolyte. 1 is in contact with a pair of long side surfaces of the inner wall 2A of the case 2 (a surface having a large area among the side surfaces of the case 2). .

Next, the operation and effect of this embodiment will be described.
In the present embodiment, the shock absorbing material 10 that is expanded by the electrolytic solution is disposed between the power generating element 8 and the inner wall 2A of the case 2, so that the power generating element 8 is connected to the inner wall 2A of the case 2 by the shock absorbing material 10. It is held with a gap in between. As a result, according to the present embodiment, even when the battery 1 is subjected to impact or vibration, problems such as breakage of the joint between the electrode plate and the current collector 7 or breakage of the electrode plate are less likely to occur. Therefore, the battery 1 excellent in impact resistance and vibration resistance can be provided.

  By the way, in order to prevent the power generation element 8 and the inner wall 2A of the case 2 from colliding with each other, it is also conceivable to dispose the cushioning material 10 in the entire gap portion formed between the power generation element 8 and the inner wall 2A of the case 2. As described above, in the battery 1 of the present embodiment, the power generation element 8 absorbs the electrolyte and expands in the winding direction of the electrode plate due to the injection of the electrolyte. 1 is in contact with the pair of long side surfaces of the inner wall 2A of the case 2, so that the cushioning material 10 is not disposed. , Collision problems are less likely to occur. However, even if the electrolytic solution is injected, the power generation element 8 hardly expands in the winding axis direction.

  Therefore, in the present embodiment, the cushioning material 10 is disposed only between the end surface 8A of the power generation element 8 that is arranged in a direction in which it is difficult to expand due to the electrolytic solution and the inner wall 2A of the case 2. As a result, according to the present embodiment, it is possible to reliably reduce the influence of shock and vibration while reducing the amount of use of the cushioning material 10.

  Further, since the cushioning material 10 used in the present embodiment expands after being immersed in the electrolyte in the case 2, the volume before being accommodated in the case 2 is expanded after being expanded in the case 2. It is a state smaller than the volume of. That is, since the volume of the cushioning material 10 is smaller than the volume of the space for accommodating the cushioning material 10 in the case 2 when performing the work of housing in the case 2, according to the present embodiment, the cushioning material 10 is The effect that the operation | work accommodated in case 2 can be performed smoothly is also acquired.

  Further, according to the present embodiment, the active material uncoated portions 9A and 9B are arranged at both ends of the power generation element 8, and the shock absorber 10 includes the right end surface 8A of the power generation element 8 and the active material uncoated portion 9A. Since it is arranged so as to cover the left end face 8A of the power generation element 8 and the active material uncoated portion 9B, even if there is a space between the active material uncoated portions 9A, 9B and the inner wall of the case 2, that space Since the cushioning material 10 is disposed on the surface, the shock resistance and the vibration resistance are excellent.

<Example>
Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.
(Production of battery of Example 1)
A battery of the form described in Embodiment 1 was produced by the following procedure.
A member in which a positive electrode terminal and a positive electrode current collector obtained by processing an aluminum metal plate material on an aluminum lid part, and a negative electrode terminal and a negative electrode current collector obtained by processing a copper metal plate material A support member was provided on a member to which a member integrated with a body was attached to produce a lid member.

  A positive electrode plate obtained by coating a strip-shaped aluminum foil with a positive electrode active material composed of lithium cobaltate and lithium manganate; and a negative electrode plate formed by coating a strip-shaped copper foil with a negative electrode active material composed of graphite. A power generation element was produced by winding through a membrane separator.

  The end of the positive electrode plate and the end of the negative electrode plate constituting the power generation element were welded and joined to the positive electrode current collector and the negative electrode current collector constituting the lid member, respectively.

By inserting into the case so that a sheet-like polystyrene resin is placed on each of the two end faces of the power generation element, joining the lid to the opening of the case, and pouring a non-aqueous electrolyte from the pouring port A battery of Example 1 was produced.
As the non-aqueous electrolyte, an electrolyte composed of dimethyl carbonate, ethyl methyl carbonate and ethylene carbonate was used.

(Production of battery of Comparative Example 1)
A battery of Comparative Example 1 was produced in the same manner as Example 1 except that no polystyrene resin was inserted into the case.

(Evaluation test)
For each of the battery of Example 1 and the battery of Comparative Example 1, the voltage was measured in advance, and a vibration test was performed by the following method.
Each battery was fixed to a vibration testing machine so that vibration was transmitted directly, and a vibration test was performed. The conditions for the vibration test were as follows. The vibration was a logarithmic sweep of a sinusoidal waveform, and the frequency 7 Hz → 200 Hz → 7 Hz was swept in 15 minutes, and this set was repeated 12 times in three directions of XYZ. Logarithmic sweep until a 18Hz from 7 Hz, maintaining the peak acceleration 1 g _n. Thereafter peak acceleration maintaining the amplitude 0.8mm increased vibration until 8 g _n. Thereafter until vibration rises 200 Hz, to maintain a peak acceleration of 8 g _n.

(Results and discussion)
For the battery of Example 1, the voltage did not decrease after the vibration test, but for the battery of Comparative Example 1, the voltage decreased after the vibration test.
With respect to the battery of Example 1, after the vibration test, the joined state of the current collector and the welded portion of the power generation element was maintained, and no deformation or dusting of the electrode plate was observed.
In the battery of Comparative Example 1, after the vibration test, the welded portion between the current collector and the power generation element was partially cut, and deformation of the electrode plate and powder falling were observed.

  From the above results, it was confirmed that according to the present invention, a battery having excellent vibration resistance can be obtained.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the example applied to a lithium ion battery was shown in the said embodiment, this invention is applicable to secondary batteries, such as a nickel metal hydride battery, and various primary batteries.
(2) In the above embodiment, the power generation element in which the positive electrode plate and the negative electrode plate are wound via the separator is shown, but the power generation element is formed by laminating the positive electrode plate and the negative electrode plate via the separator. Also good.
(3) In the above embodiment, the battery in which the cushioning material is disposed between the end surface of the power generation element and the case inner wall is shown. However, the buffer material may be disposed between the outer surface other than the end surface of the power generation element and the case inner wall, You may arrange | position in the whole region of the clearance gap part formed between the outer surface of this, and a case inner wall. Moreover, you may arrange | position a buffer material partially in the space between the end surface of an electric power generation element and a case inner wall.
(4) In the above embodiment, the positive electrode plate is provided with an aluminum foil and the negative electrode plate is provided with a copper foil. However, even when the present invention is applied to a lithium ion battery, the material of the electrode plate Is not limited to this.
(5) In the said embodiment, although the buffer material arrange | positioned so that an end surface and an active material non-application part may be covered in the both ends of an electric power generation element, the buffer material does not cover the active material non-application part. Good. Moreover, the buffer material may be arrange | positioned so that the end surface of an electric power generation element and an active material non-application part may be covered in one edge part of an electric power generation element.

DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Case 2A ... Inner wall of case 4 ... Electrode terminal 4A ... Positive electrode terminal 4B ... Negative electrode terminal 8 ... Power generation element 8A ... End face of power generation element 9A ... Active material uncoated part (of positive electrode plate) 9B ... Active material uncoated part of (negative electrode plate) 10 ... Buffer material 19A ... Positive electrode plate 19B ... Negative electrode plate

Claims (4)

A battery comprising a power generation element formed by laminating or winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, an electrolytic solution, and a case that accommodates the power generation element in a state immersed in the electrolytic solution,
A battery comprising a buffer material made of a material that is expanded by the electrolyte solution between the power generation element and an inner wall of the case. The battery according to claim 1, wherein the cushioning material is disposed between an end face of the power generation element and an inner wall of the case. At least one of the positive electrode plate and the negative electrode plate has an active material uncoated portion where no active material is applied to an end portion, and the active material uncoated portion is disposed at an end portion of the power generation element,
The battery according to claim 1, wherein the buffer material is disposed so as to cover an end face of the power generation element and the active material uncoated portion. The battery according to any one of claims 1 to 3, wherein the buffer material is made of polyvinylidene fluoride or a mixed resin of polyvinylidene fluoride and polystyrene.

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