Patent Description:
A cylindrical battery has a bottomed cylindrical outer can and a sealing assembly that seals an opening of the outer can (see, for example, Patent Literature <NUM>). In the cylindrical battery disclosed in Patent Literature <NUM>, the outer can is caulked in a radial direction of the sealing assembly to compress a gasket interposed between the outer can and the sealing assembly. In such a lateral caulking-type cylindrical battery, there is no need to provide a groove between the gasket and an electrode assembly in the outer can, so that the volume required to house the electrode assembly can be increased and thereby a larger capacity of the battery can be achieved. A conventional cylindrical battery provides such a groove and an insulating plate arranged and fixed between the electrode assembly and the sealing assembly (see Patent Literature <NUM>: <CIT>).

Patent Literature <NUM>: <CIT> Patent Literature <NUM>: <CIT>.

However, in the cylindrical battery disclosed in Patent Literature <NUM>, there is no disclosure about an insulating plate arranged between the electrode assembly and the sealing assembly nor about fixing of the insulating plate. When the insulating plate is not fixed in the cylindrical battery and in this state, a negative electrode plate extends due to overcharging or the like and causes dislocation or inclination of the insulating plate, a contact between a negative electrode plate and a positive electrode lead or a contact between the negative electrode plate and the sealing assembly may occur and cause an internal short circuit.

It is an advantage of the present disclosure to provide a cylindrical battery capable of fixing an insulating plate arranged between an electrode assembly and a sealing assembly.

A cylindrical battery in one aspect of the present disclosure is a cylindrical battery comprises: an electrode assembly having a positive electrode plate and a negative electrode plate wound through a separator; an electrolyte;
a bottomed cylindrical outer can configured to house the electrode assembly and the electrolyte; a sealing plate configured to seal an opening of the outer can; a gasket arranged on a circumferential edge of the sealing plate; and an insulating plate arranged above the electrode assembly to insulate the electrode assembly and the sealing plate. The gasket is compressed in a radial direction between an end face of the circumferential edge of the sealing plate and the outer can, and the outer can has a locking part to be engaged with the circumferential edge of the insulating plate.

According to one aspect of the present disclosure, the insulating plate arranged between the electrode assembly and the sealing assembly can be fixed. This prevents occurrence of an internal short circuit.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Shapes, materials, and the number described below are merely exemplary, and modifications are possible as appropriate according to the specification of the cylindrical battery. In all the drawings shown below, like components are designated by like reference signs.

With reference to <FIG>, a cylindrical battery <NUM> as an example of the embodiment will be described. <FIG> is a sectional view of the cylindrical battery <NUM>.

As shown in <FIG>, the cylindrical battery <NUM> comprises an electrode assembly <NUM>, an electrolyte, an outer can <NUM> that houses the electrode assembly <NUM> and the electrolyte, and a sealing plate <NUM> that seals an opening 20A of the outer can <NUM>. The electrode assembly <NUM> has a structure including a positive electrode plate <NUM>, a negative electrode plate <NUM>, and a separator <NUM>, the positive electrode plate <NUM> and the negative electrode plate <NUM> being wound into a spiral shape through the separator <NUM>. The cylindrical battery <NUM> further comprises an upper insulating plate <NUM> arranged above the electrode assembly <NUM> and a lower insulating plate <NUM> arranged below the electrode assembly <NUM>. Hereinafter, for convenience of description, the side of the cylindrical battery <NUM> closer to the sealing plate <NUM> (the side of the outer can <NUM> closer to the opening 20A) is defined as an upper side, and the bottom side of the outer can <NUM> is defined as a lower side.

The positive electrode plate <NUM> has a positive electrode core, and a positive electrode mixture layer formed on at least one face of the core. As the positive electrode core, a metal foil that is stable in a potential range of the positive electrode plate <NUM>, such as aluminum and aluminum alloy, a film with the metal arranged on its surface layer may be used. The positive electrode mixture layer preferably contains a positive electrode active material, a conductive agent such as acetylene black, and a binding agent such as polyvinylidene fluoride, and is formed on both the faces of the positive electrode core. As the positive electrode active material, lithium-transition metal composite oxide is used, for example. The positive electrode plate <NUM> can be manufactured by coating the positive electrode core with positive electrode mixture slurry containing the positive electrode active material, a conductive agent, a binding agent, and the like, drying the coating, and then compressing the coating to form a positive electrode mixture layer on both the faces of the core.

The negative electrode plate <NUM> has a negative electrode core, and a negative electrode mixture layer formed on at least one face of the core. As the negative electrode core, a metal foil that is stable in a potential range of the negative electrode plate <NUM>, such as coper and copper alloy, a film with the metal arranged on its surface layer may be used. The negative electrode mixture layer preferably contains a negative electrode active material and a binding agent such as styrene-butadiene rubber (SBR), and is formed on both the faces of the negative electrode core. As the negative electrode active material, graphite, silicon-containing compounds, and the like, are used, for example. The negative electrode plate <NUM> can be manufactured by coating the negative electrode core with negative electrode mixture slurry containing a negative electrode active material, a binding agent, and the like, drying the coating, and then compressing the coating to form a negative electrode mixture layer on both the faces of the core.

As the electrolyte, non-aqueous electrolyte is used, for example. The non-aqueous electrolyte contains non-aqueous solvent and electrolyte salt dissolved in non-aqueous solvent. As the non-aqueous solvent, esters, ethers, nitriles, amides, and a mixture of two or more of the group consisting of esters, ethers, nitriles, and amides can be used. The non-aqueous solvent may contain halogen substitutions that replace at least some of hydrogen atoms in these solvents with halogen atoms such as fluorine. The non-aqueous electrolyte is not limited to liquid electrolyte, and may be solid electrolyte. As the electrolyte salt, lithium salt such as LiPF6 is used. The type of electrolyte is not particularly limited, and may be aqueous electrolyte.

The upper insulating plate <NUM> is a member arranged above the electrode assembly <NUM> to insulate the electrode assembly <NUM> and the sealing plate <NUM>. The upper insulating plate <NUM> is formed into a disk shape having an opening 15A at the center in a radial direction and a through-hole that allows insertion of the positive electrode lead <NUM>. The diameter of the upper insulating plate <NUM> is larger than an inner diameter of a first cylinder part 20B of the outer can <NUM> described later, and smaller than a maximum inner diameter of a locking part 20D described later. The positive electrode lead <NUM> connected to the positive electrode plate <NUM> extends through the through-hole of the upper insulating plate <NUM> toward the sealing plate <NUM>. The positive electrode lead <NUM> is connected by welding or the like to a central bottom of the sealing plate <NUM>, so that the sealing plate <NUM> serves as a positive electrode external terminal.

The lower insulating plate <NUM> is arranged below the electrode assembly <NUM> to insulate the electrode assembly <NUM> and the outer can <NUM>. The lower insulating plate <NUM> is formed into a disk shape having an opening formed at the center in the radial direction. The negative electrode lead <NUM> connected to the negative electrode plate <NUM> extends outside the lower insulating plate <NUM> along the bottom of the outer can <NUM>. The negative electrode lead <NUM> is connected by welding or the like to the inside surface of the bottom part of the outer can <NUM>, so that the outer can <NUM> serves as a negative electrode external terminal.

As described above, the cylindrical battery <NUM> comprises the outer can <NUM> and the sealing plate <NUM> to seal the opening 20A of the outer can <NUM>. The outer can <NUM> is a bottomed cylindrical metal container having a bottom and a cylinder part. The bottom has a disk shape, and the cylinder part is formed into a cylindrical shape along an outer edge of the bottom. The cylinder part, which is formed above the bottom, includes a first cylinder part 20B that houses the electrode assembly <NUM>, a second cylinder part 20C that is thinner than the first cylinder part 20B to allow the gasket <NUM> to be compressed so as to fix the sealing plate <NUM> by caulking, and the locking part 20D formed between the first cylinder part 20B and the second cylinder part 20C to engage with a circumferential edge 15B of the upper insulating plate <NUM>.

The first cylinder part 20B is a cylindrical portion that houses the electrode assembly <NUM>. The first cylinder part 20B has a height substantially identical to the height of the electrode assembly <NUM>.

The second cylinder part 20C is a cylindrical portion that allows the gasket <NUM> to be compressed to fix the sealing plate <NUM> by caulking. The second cylinder part 20C preferably has a thickness about <NUM>/<NUM> to <NUM>/<NUM> of the thickness of the first cylinder part 20B. The second cylinder part 20C is caulked in the radial direction and formed to be smaller in diameter than the first cylinder part 20B. The second cylinder part 20C may have protrusions formed in a circumferential direction on its inner surface. This can increase the force to compress the gasket <NUM>.

The locking part 20D is a cylindrical portion formed between the first cylinder part 20B and the second cylinder part 20C to engage with the circumferential edge 15B of the upper insulating plate <NUM>. The locking part 20D is formed so as to include an inner portion of an upper end face 20E of the first cylinder part 20B, and an inclination part 20F connecting between the second cylinder part 20C and an external portion of the upper end face 20E of the first cylinder part 20B. The inclination part 20F is formed to have a smaller diameter toward the upper side. The thickness of the inclination part 20F is identical to the thickness of the second cylinder part 20C.

The locking part 20D engages with the circumferential edge 15B of the upper insulating plate <NUM>, so that the upper insulating plate <NUM> is fixed to the outer can <NUM>. More specifically, the circumferential edge 15B of the upper insulating plate <NUM> is interposed and fixed between the inner circumferential side of the upper end face 20E of the first cylinder part 20B and the inclination part 20F.

The locking part 20D can fix the upper insulating plate <NUM>. Hence, in the event where, for example, the upper insulating plate <NUM> shifts and inclines, and the negative electrode plate <NUM> is elongated during repeated charge and discharge cycles, there is no risk of internal short circuits caused due to a contact between the negative electrode plate <NUM> and the positive electrode lead <NUM>, or a contact between the negative electrode plate <NUM> and the sealing plate <NUM> in the opening 15A of the upper insulating plate <NUM>.

The sealing plate <NUM>, which is a metal valve, can include other members such as a terminal cap arranged on its upper face. The sealing plate <NUM> is configured such a center 30B on the inner circumferential side of the circumferential edge 30A projects toward the electrode assembly <NUM> from the circumferential edge 30A. The bottom of the center 30B is connected to the positive electrode plate <NUM> via the positive electrode lead <NUM>, so that the sealing plate <NUM> serves as a positive electrode terminal of the cylindrical battery <NUM>. Since the sealing plate <NUM> is constituted of a smaller number of components, cost and time required for processing and assembling can be reduced.

The gasket <NUM> is present between the opening 20A of the outer can <NUM> and the sealing plate <NUM> that seals the opening 20A. The gasket <NUM> is a flexible insulating material. When the gasket <NUM> is compressed in the radial direction of the sealing plate <NUM> while providing insulation between the sealing plate <NUM> that is a positive electrode terminal and the outer can <NUM> that is a negative electrode terminal, sealability inside the cylindrical battery <NUM> is ensured.

With reference to <FIG>, a manufacturing step of the cylindrical battery <NUM> will be described. <FIG> are schematic views showing part of the manufacturing step.

In the manufacturing step of the cylindrical battery <NUM>, the electrode assembly <NUM> and the bottomed cylindrical outer can <NUM>, having the first cylinder part 20B and the second cylinder part 20C by drawing of a steel sheet, are first manufactured. Then, the electrode assembly <NUM> is inserted into the first cylinder part 20B of the outer can <NUM>.

Then, as shown in <FIG>, the upper insulating plate <NUM> is engaged with the inside of the upper end face 20E of the first cylinder part 20B of the outer can <NUM>. Furthermore, as shown in <FIG>, electrolyte is injected into the outer can <NUM>, and the sealing plate <NUM> is inserted into the second cylinder part 20C of the outer can <NUM>. The second cylinder part 20C of the outer can <NUM> is caulked in the radial direction from the outside of the outer can <NUM> such that the opening 20A of the outer can <NUM> is sealed by the second cylinder part 20C through the gasket <NUM>.

When the second cylinder part 20C of the outer can <NUM> is caulked in the radial direction, a lower part of the second cylinder part 20C is formed as the inclination part 20F, and the circumferential edge 15B of the upper insulating plate <NUM>, which has been engaged with the upper end face 20E of the outer can <NUM>, is engaged with the locking part 20D formed by the upper end face 20E and the inclination part 20F.

With reference to <FIG>, a cylindrical battery <NUM> as another example of the embodiment will be described. <FIG> is a sectional view of the cylindrical battery <NUM>.

As shown in <FIG>, the cylindrical battery <NUM> comprises an electrode assembly <NUM>, an electrolyte, an outer can <NUM> that houses the electrode assembly <NUM> and the electrolyte, and a sealing plate <NUM> that seals an opening 40A of the outer can <NUM>. The cylindrical battery <NUM> further comprises an upper insulating plate <NUM> arranged above the electrode assembly <NUM> and a lower insulating plate <NUM> arranged below the electrode assembly <NUM>. Since the cylindrical battery <NUM> in this example is similar to the cylindrical battery described in <FIG>, description thereof will be omitted except for the upper insulating plate <NUM> and the outer can <NUM>.

The upper insulating plate <NUM> is a member arranged above the electrode assembly <NUM> to insulate the electrode assembly <NUM> and the sealing plate <NUM>. The upper insulating plate <NUM> is formed into a disk shape having an opening 15A formed at the center in the radial direction, and a through-hole. The diameter of the upper insulating plate <NUM> is larger than an inner diameter of a housing part 40B of the outer can <NUM> described later, and smaller than a maximum inner diameter of a locking part 40D described later.

The outer can <NUM> is a bottomed cylindrical metal container having a bottom and a cylinder part. The bottom has a disk shape, and the cylinder part is formed in a cylindrical shape along an outer circumferential edge of the bottom. The cylinder part, which is formed above the bottom, includes a housing part 40B that houses the electrode assembly <NUM>, a caulking part 40C that allows the gasket <NUM> to be compressed to fix the sealing plate <NUM> by caulking, and a locking part 40D formed between the housing part 40B and the caulking part 40C to engage with a circumferential edge 15B of the upper insulating plate <NUM>. The housing part 40B, the locking part 40D, and the caulking part 40C are identical in thickness.

The housing part 40B is a cylindrical portion that houses the electrode assembly <NUM>. The housing part 40B has a height substantially identical to the height of the electrode assembly <NUM>.

The caulking part 40C is a cylindrical portion to allow the gasket <NUM> to be compressed so as to fix the sealing plate <NUM> by caulking. The caulking part 40C is caulked in the radial direction and formed to be smaller in diameter than the locking part 40D. The caulking part 40C may have protrusions formed in a circumferential direction on its inner surface. This can increase the force to compress the gasket <NUM>.

The locking part 40D is a portion formed between the housing part 40B and the caulking part 40C to engage with the circumferential edge 15B of the upper insulating plate <NUM>. The locking part 40D is formed so as to include a diameter enlarged part 40E that is enlarged in diameter toward the upper side from the housing part 40B, and a connection part 40F that connects the diameter enlarged part 40E and the caulking part 40C.

The locking part 40D engages with the circumferential edge 15B of the upper insulating plate <NUM>, and the upper insulating plate <NUM> is fixed to the outer can <NUM>. More specifically, the circumferential edge 15B of the upper insulating plate <NUM> is interposed and fixed between the diameter enlarged part 40E and the connection part 40F. The locking part 40D can fix the upper insulating plate <NUM>.

With reference to <FIG>, a manufacturing step of the cylindrical battery <NUM> will be described. <FIG> are schematic views showing part of the manufacturing process.

In the manufacturing process of the cylindrical battery <NUM>, the electrode assembly <NUM> and the outer can <NUM> are first manufactured, the outer can <NUM> having the housing part 40B that houses the electrode assembly <NUM> by drawing of a steel sheet and a diameter enlarged part <NUM> enlarged in diameter toward the upper side (a portion corresponding to the diameter enlarged part 40E, the connection part 40F, and the caulking part 40C of the cylindrical battery <NUM>). Then, the electrode assembly <NUM> is inserted into the housing part 40B of the outer can <NUM>.

Then, as shown in <FIG>, the upper insulating plate <NUM> is engaged with a middle portion of the diameter enlarged part <NUM> of the outer can <NUM>. Furthermore, as shown in <FIG>, electrolyte is injected into the outer can <NUM>, and the sealing plate <NUM> is inserted into the diameter enlarged part <NUM> of the outer can <NUM>. Then, the diameter enlarged part <NUM> of the outer can <NUM> is caulked in the radial direction from the outside of the outer can <NUM> such that the opening 40A of the outer can <NUM> is sealed by the caulking part 40C through the gasket <NUM>.

When the caulking part 40C of the outer can <NUM> is formed, a lower part of the caulking part 40C is formed as the connection part 40F, and the circumferential edge 15B of the upper insulating plate <NUM>, which has been engaged with the middle portion of the diameter enlarged part <NUM> of the outer can <NUM>, is engaged with the locking part 40D formed by the diameter enlarged part 40E and the connection part 40F.

It should be understood that the present invention is not limited to the embodiment and modifications disclosed, and various modifications and changes are possible without departing from the scope of the claims of the present application.

Claim 1:
A cylindrical battery (<NUM>), comprising:
an electrode assembly (<NUM>) having a positive electrode plate (<NUM>) and a negative electrode plate (<NUM>) wound through a separator (<NUM>);
an electrolyte;
a bottomed cylindrical outer can (<NUM>) configured to house the electrode assembly (<NUM>) and the electrolyte;
a sealing plate (<NUM>) configured to seal an opening (20A) of the outer can (<NUM>);
a gasket (<NUM>) arranged on a circumferential edge (30A) of the sealing plate (<NUM>); and
an insulating plate (<NUM>) arranged between the electrode assembly (<NUM>) and the sealing plate (<NUM>), wherein
the gasket (<NUM>) is compressed in a radial direction between an end face of the circumferential edge (30A) of the sealing plate (<NUM>) and the outer can (<NUM>), and
the outer can (<NUM>) has a locking part (20D) to be engaged with a circumferential edge (15B) of the insulating plate (<NUM>).