Patent Description:
PTL <NUM> (<CIT>) describes the art of stacking cells in an all-solid state battery to realize a parallel connection or serial connection of a plurality of cells. In the art described in PTL <NUM>, insulating boards are arranged at the top side and bottom side of a power generating element including positive electrode current collector, positive electrode, solid electrolyte, negative electrode, and negative electrode current collector stacked together. A metal pattern (extraction electrode) is provided at the top surface of the insulating board at the top side, while a metal pattern (extraction electrode) is provided at the bottom surface of the insulating board at the bottom side. Due to this, a unit cell of an all-solid-state battery is configured.

In the art described in PTL <NUM>, if, for example, two unit cells are stacked, the metal pattern provided at the bottom surface of the bottom side insulating board of the top side unit cell and the metal pattern provided at the top surface of the top side insulating board of the bottom side unit cell are made to contact. That is, in the art described in PTL <NUM>, if, for example, two unit cells are stacked, between the power generating element of the top side unit cell and the power generating element of the bottom side unit cell, the bottom side insulating board of the top side unit cell, the metal pattern provided at the bottom surface of the bottom side insulating sheet of the top side unit cell, the top side insulating board of the bottom side unit cell, and the metal pattern provided at the top surface of the top side insulating board of the bottom side unit cell exist. For this reason, in the art described in PTL <NUM>, it is not possible to sufficiently keep down the dimensions in the stacking direction of a stacked battery configured by stacking a plurality of unit cells.

In consideration of the above-mentioned point, the present disclosure has as its object the provision of a stacked battery able to sufficiently keep down the dimensions in the stacking direction. The subject matter of the present invention is defined in the appended claims.

According to the present disclosure, it is possible to sufficiently keep down the dimensions of a stacked battery in the stacking direction.

<FIG> schematically shows one example of a cross-section of a stacked battery <NUM> of the first embodiment.

<FIG> shows a positive electrode current collector <NUM> of a cell <NUM>-<NUM> included in the stacked battery <NUM> of the first embodiment shown in <FIG> pulled out.

<FIG> shows a negative electrode current collector <NUM> of the cell <NUM>-<NUM> included in the stacked battery <NUM> of the first embodiment shown in <FIG> pulled out.

<FIG> is a view of the cell <NUM>-<NUM> seen from below <FIG>.

<FIG> is a view of a cell <NUM>-<NUM> seen from above <FIG>.

<FIG> is a photo of a prototype of the cell <NUM>-<NUM> shown in <FIG>.

<FIG> is a view of the cell <NUM>-<NUM> seen from a side of the cell <NUM>-<NUM> in the stacking direction of the stacked battery <NUM> of a second embodiment.

<FIG> is a view of the cell <NUM>-<NUM> seen from a side of the cell <NUM>-<NUM> in the stacking direction of the stacked battery <NUM> of the second embodiment.

<FIG> is a cross-sectional view of an assembly of positive electrode <NUM>, separator <NUM>, and negative electrode <NUM> configuring part of the stacked battery <NUM> of an example.

<FIG> is a view of the assembly shown in <FIG> seen from above <FIG>.

<FIG> is a cross-sectional view of the assembly which is in a state in which positive electrode current collector <NUM>, negative electrode current collector <NUM>, and insulating material (seal material) <NUM> are added to the assembly shown in <FIG>.

<FIG> is a cross-sectional view of the cell <NUM>-<NUM> configured by second part <NUM> and third part <NUM> of the positive electrode current collector <NUM> and second part <NUM> and third part <NUM> of the negative electrode current collector <NUM> of the assembly shown in <FIG> being wound around the positive electrode <NUM>, the separator <NUM>, and the negative electrode <NUM> via first insulating material <NUM> and second insulating material <NUM>.

<FIG> is a view of the cell <NUM>-<NUM> shown in <FIG> seen from above <FIG>.

<FIG> is a cross-sectional view of the stacked battery <NUM> configured by stacking the cell <NUM>-<NUM> shown in <FIG> and the cell <NUM>-<NUM> configured in the same way as the cell <NUM>-<NUM>.

<FIG> is a view showing in comparison a cell capacity of the cell <NUM>-<NUM> and the cell capacity of the cell <NUM>-<NUM> and cell capacity of the stacked battery <NUM>.

Below, embodiments of a stacked battery of the present disclosure will be explained with reference to the drawings.

<FIG> are views schematically showing one example of a stacked battery <NUM> of a first embodiment. In more detail, <FIG> schematically shows the example of a cross-section of the stacked battery <NUM> of the first embodiment, <FIG> shows a positive electrode current collector <NUM> of a cell <NUM>-<NUM> included in the stacked battery <NUM> of the first embodiment shown in <FIG> pulled out, and <FIG> shows a negative electrode current collector <NUM> of the cell <NUM>-<NUM> included in the stacked battery <NUM> of the first embodiment shown in <FIG> pulled out. <FIG> are views schematically showing one example of cells <NUM>-<NUM> and <NUM>-<NUM> included in the stacked battery <NUM> of the first embodiment. In more detail, <FIG> is a view of the cell <NUM>-<NUM> seen from below <FIG>, while <FIG> is a view of a cell <NUM>-<NUM> seen from above <FIG>. <FIG> is a photo of a prototype of the cell <NUM>-<NUM> shown in <FIG>.

In the example shown in <FIG>, the stacked battery <NUM> includes the cell <NUM>-<NUM> and the cell <NUM>-<NUM> and is configured by stacking the cell <NUM>-<NUM> and the cell <NUM>-<NUM>.

In another example, the stacked battery <NUM> includes any number of cells other than two (however, several) and is configured by stacking these cells.

In the example shown in <FIG>, the cell <NUM>-<NUM> and the cell <NUM>-<NUM> have the same configurations.

In another example, the respective configurations of the plurality of cells included in the stacked battery <NUM> need not be completely the same.

In the example shown in <FIG>, the cell <NUM>-<NUM> has electrode body <NUM>, first insulating material <NUM>, and second insulating material <NUM>.

The first insulating material <NUM> and second insulating material <NUM> are configured by for example resin material having electrical insulation function and sealing function.

In more detail, in the example shown in <FIG>, the first insulating material <NUM> and second insulating material <NUM> are configured by PP (polypropylene).

In another example, the first insulating material <NUM> and second insulating material <NUM> may be configured by resin material other than PP film (however, resin material having the electrical insulation function and the sealing function).

In the example shown in <FIG>, the electrode body <NUM> includes positive electrode current collector <NUM>, positive electrode <NUM>, separator <NUM> including electrolyte (for example, the separator <NUM> in which the electrolyte is impregnated), negative electrode <NUM>, and negative electrode current collector <NUM> stacked in that order.

As the positive electrode current collector <NUM>, anything able to be used as the positive electrode current collector of this type of battery can be used without particular limitation. Typically, the positive electrode current collector <NUM> is, for example, configured by a metal material having good conductivity such as aluminum, nickel, titanium, and stainless steel.

The positive electrode current collector <NUM> is preferably a collector having oxidation resistance. In the example shown in <FIG>, as the positive electrode current collector <NUM>, aluminum foil is used.

As the positive electrode material forming the positive electrode <NUM>, for example, LiNiCoMn, SE (solid electrolyte) (LiI-LiBr-Li<NUM> S-P<NUM> S<NUM> ), VGCF (vapor grown carbon fibers), and SBR (styrene-butadiene rubber) mixed together can be used. Positive electrode active substance, conductivity aid, and adhesive material contained in the positive electrode <NUM> are not particularly designated.

That is, the positive electrode <NUM> may also contain electrolyte. If the positive electrode <NUM> contains the electrolyte, the electrolyte is preferably a solid electrolyte with a high heat resistance (sulfide or oxide). This is because a solid electrolyte which is strong against heat is necessary to enable hot bonding of the first insulating material <NUM> and second insulating material <NUM> used as the sealing material.

For example, an positive electrode composite paste obtained by mixing positive electrode active substance, conductivity aid, and binding material (adhesive material) and organic solvent (for example, N-methyl-<NUM>-pyrrolidone (NMP)) can be coated and dried on the positive electrode current collector <NUM> to form an positive electrode composite layer on the positive electrode current collector <NUM>, then the positive electrode composite layer is rolled to a predetermined thickness to thereby prepare the positive electrode <NUM>. As the positive electrode active substance, for example, LiCoO<NUM> , LiNiO<NUM> , LiNiaCobO<NUM> (a+b=<NUM>, <NUM><a<<NUM>, <NUM><b<<NUM>), LiMnO<NUM> , LiMn<NUM> O<NUM> , LiNia Cob Mnc O<NUM> (a+b+c=<NUM>, <NUM><a<<NUM>, <NUM><b<<NUM>, <NUM><c<<NUM>), LiFePO<NUM> , etc. can be used. Further, as the conductivity aid, for example, acetylene black (AB) etc. can be used. As binder material, for example, polyvinylidene fluoride (PVdF) etc. can be used.

The electrolyte included in the separator <NUM> is preferably the solid electrolyte having high heat resistance for the above-mentioned reason.

In the example shown in <FIG>, as the material forming the separator <NUM>, SE and SBR mixed together are used.

The separator <NUM> may be substantially comprised of solid electrolyte material. The separator <NUM>, for example, may further contain a binder etc. The separator <NUM> can include any solid electrolyte material. The separator <NUM>, for example, may include Li<NUM>S-P<NUM> S<NUM> -based solid electrolyte etc..

As negative electrode material forming the negative electrode <NUM>, for example, graphite, SE (LiI-LiBr-Li<NUM> S-P<NUM> S<NUM> ), VGCF, and SBR mixed together may be used. Negative electrode active substance, conductivity aid, and adhesive material contained in the negative electrode <NUM> are not particularly designated.

That is, the negative electrode <NUM> may contain electrolyte. If the negative electrode <NUM> contains the electrolyte, the electrolyte is preferably the solid electrolyte with high heat resistance for the above-mentioned reason.

As the negative electrode current collector <NUM>, ones able to be used as the negative electrode current collector of this type of battery can be used without particular limitation.

The negative electrode current collector <NUM> is preferably a current collector having reduction resistance. In the example shown in <FIG>, as the negative electrode current collector <NUM>, nickel foil is used.

As shown in <FIG>, the positive electrode current collector <NUM> has first part <NUM>, second part <NUM>, and third part <NUM>. The third part <NUM> extends in the stacking direction (up-down direction of <FIG>) of the cell <NUM>-<NUM> and connects the first part <NUM> and second part <NUM>.

As shown in <FIG>, the negative electrode current collector <NUM> has first part <NUM>, second part <NUM>, and third part <NUM>. The third part <NUM> extends in the stacking direction (up-down direction of <FIG>) of the cell <NUM>-<NUM> and connects the first part <NUM> and second part <NUM>.

As shown in <FIG>, the first insulating material <NUM> is arranged on an opposite side (top side of <FIG>) of the positive electrode <NUM> across the first part <NUM> of the positive electrode current collector <NUM>.

As shown in <FIG>, the second insulating material <NUM> is arranged on an opposite side (bottom side of <FIG>) of the negative electrode <NUM> across the first part <NUM> of the negative electrode current collector <NUM>.

As shown in <FIG>, the second part <NUM> of the positive electrode current collector <NUM> is arranged on an opposite side (bottom side of <FIG>) of the first part <NUM> of the negative electrode current collector <NUM> across the second insulating material <NUM>. The second part <NUM> of the negative electrode current collector <NUM> is arranged on an opposite side (top side of <FIG>) of the first part <NUM> of the positive electrode current collector <NUM> across the first insulating material <NUM>.

As shown in <FIG>, the third part <NUM> of the positive electrode current collector <NUM> is arranged on an opposite side (right side of <FIG>) of the third part <NUM> of the negative electrode current collector <NUM> across the positive electrode <NUM>, the separator <NUM> including the electrolyte, and the negative electrode <NUM>.

As shown in <FIG>, the first insulating material <NUM> is arranged so as not to overlap the second insulating material <NUM> in the stacking direction (up-down direction of <FIG>) of the cell <NUM>-<NUM>. That is, the position of the first insulating material <NUM> in the left-right direction of <FIG> and the position of the second insulating material <NUM> in the left-right direction of <FIG> are offset (made different).

As shown in <FIG>, the first insulating material <NUM> is arranged so as not to overlap the second part <NUM> of the positive electrode current collector <NUM> in the stacking direction of the cell <NUM>-<NUM>. That is, the position of the first insulating material <NUM> in the left-right direction of <FIG> and the position of the second part <NUM> of the positive electrode current collector <NUM> in the left-right direction of <FIG> are offset (made different).

As shown in <FIG>, the second part <NUM> of the negative electrode current collector <NUM> is arranged so as not to overlap the second insulating material <NUM> in the stacking direction of the cell <NUM>-<NUM>. That is, the position of the second part <NUM> of the negative electrode collector <NUM> in the left-right direction of <FIG> and the position of the second insulating material <NUM> in the left-right direction of <FIG> are offset (made different).

As shown in <FIG>, the second part <NUM> of the negative electrode current collector <NUM> is arranged so as not to overlap the second part <NUM> of the positive electrode current collector <NUM> in the stacking direction of the cell <NUM>-<NUM>. That is, the position of the second part <NUM> of the negative electrode current collector <NUM> in the left-right direction of <FIG> and the position of the second part <NUM> of the positive electrode current collector <NUM> in the left-right direction of <FIG> are offset (made different).

In the example shown in <FIG>, the respective thicknesses of the cells <NUM>-<NUM> and <NUM>-<NUM> in the stacking direction are, for example, <NUM> to <NUM>.

As a result, in the example shown in <FIG>, the second part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> and the first part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> can be made to contact and the first part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> and the second part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> can be made to contact in order to stack the cell <NUM>-<NUM> and the cell <NUM>-<NUM> and can keep down the dimensions of the stacked battery <NUM> in the stacking direction.

Further, in the example shown in <FIG>, by stacking the cell <NUM>-<NUM> and the cell <NUM>-<NUM> in this way, it is possible to easily connect in parallel the cell <NUM>-<NUM> and the cell <NUM>-<NUM>.

The stacked battery <NUM> of a second embodiment is configured in the same way as the stacked battery <NUM> of the above-mentioned first embodiment except for the points explained later.

<FIG> are views schematically showing one example of the cells <NUM>-<NUM> and <NUM>-<NUM> included in the stacked battery <NUM> of the second embodiment. In more detail, <FIG> is a view of the cell <NUM>-<NUM> seen from a side of the cell <NUM>-<NUM> in the stacking direction of the stacked battery <NUM> of the second embodiment, while <FIG> is a view of the cell <NUM>-<NUM> seen from a side of the cell <NUM>-<NUM> in the stacking direction of the stacked battery <NUM> of the second embodiment.

As shown in <FIG>, <FIG>, when making the second part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> and the first part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> contact to stack the cell <NUM>-<NUM> and the cell <NUM>-<NUM>, so long as the second part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> does not contact either of the second part <NUM> of the negative electrode current collector <NUM> and first insulating material <NUM> of the cell <NUM>-<NUM>, it is possible to set the shape of the second part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> shown in <FIG> and <FIG> to any shape. Further, when making the first part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> and the second part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> contact to stack the cell <NUM>-<NUM> and the cell <NUM>-<NUM>, so long as the second part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> does not contact either of the second part <NUM> of the positive electrode current collector <NUM> and second insulating material <NUM> of the cell <NUM>-<NUM>, it is possible to set the shape of the second part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM> shown in <FIG> and <FIG> to any shape.

<FIG> are views for explaining a process of production of the stacked battery <NUM> of an example. In more detail, <FIG> is a cross-sectional view of an assembly of the positive electrode <NUM>, the separator <NUM>, and the negative electrode <NUM> configuring part of the stacked battery <NUM> of the example, while <FIG> is a view of the assembly shown in <FIG> seen from above <FIG>. <FIG> is a cross-sectional view of the assembly which is in a state in which the positive electrode current collector <NUM>, the negative electrode current collector <NUM>, and insulating material (seal material) <NUM> are added to the assembly shown in <FIG>, while <FIG> is a view of the assembly shown in <FIG> seen from above <FIG>. <FIG> is a cross-sectional view of the cell <NUM>-<NUM> configured by the second part <NUM> and the third part <NUM> of the positive electrode current collector <NUM> and the second part <NUM> and the third part <NUM> of the negative electrode current collector <NUM> of the assembly shown in <FIG> being wound around the positive electrode <NUM>, the separator <NUM>, and the negative electrode <NUM> via the first insulating material <NUM> and the second insulating material <NUM>, while <FIG> is a view of the cell <NUM>-<NUM> shown in <FIG> seen from above <FIG>. <FIG> is a cross-sectional view of the stacked battery <NUM> configured by stacking the cell <NUM>-<NUM> shown in <FIG> and the cell <NUM>-<NUM> configured in the same way as the cell <NUM>-<NUM>. <FIG> is a view showing in comparison a cell capacity of the cell <NUM>-<NUM> and the cell capacity of the cell <NUM>-<NUM> and the cell capacity of the stacked battery <NUM>.

In the example shown in <FIG>, as the positive electrode material forming the positive electrode <NUM>, LiNiCoMn, SE(LiI-LiBr-Li<NUM> S-P<NUM> S<NUM> ), VGCF, and SBR mixed together were used. As the negative electrode material forming the negative electrode <NUM>, graphite, SE (LiI-LiBr-Li<NUM> S-P<NUM> S<NUM> ), VGCF, and SBR mixed together were used. As the material forming the separator <NUM>, SE and SBR mixed together were used. As the first insulating material <NUM>, the second insulating material <NUM>, and the insulating material (sealing material) <NUM>, PP film was used. As the positive electrode current collector <NUM>, aluminum foil was used. As the negative electrode current collector <NUM>, nickel foil was used.

In the state shown in <FIG>, heating at <NUM> for <NUM> minute was performed to seal the positive electrode <NUM>, the separator <NUM>, and the negative electrode <NUM> positioned between the positive electrode current collector <NUM> and the negative electrode current collector <NUM> by the insulating material (sealing material) <NUM>.

In the state shown in <FIG>, the second part <NUM> and the third part <NUM> of the positive electrode current collector <NUM> and the second part <NUM> and the third part <NUM> of the negative electrode current collector <NUM> were wound around the positive electrode <NUM>, the separator <NUM>, the negative electrode <NUM>, and the insulating material (sealing material) <NUM>. Heating at <NUM> for <NUM> minute was performed to seal it by the first insulating material <NUM> and the second insulating material <NUM>.

The cell <NUM>-<NUM> shown in <FIG> is configured by sealing the electrode body <NUM> including the positive electrode current collector <NUM>, the positive electrode <NUM>, the separator <NUM> including the electrolyte, the negative electrode <NUM>, and the negative electrode current collector <NUM> stacked in that order, by the positive electrode current collector <NUM>, the negative electrode current collector <NUM>, the first insulating material <NUM>, and the second insulating material <NUM>.

In the state shown in <FIG>, heating at <NUM> for <NUM> minute was performed to make the second insulating material <NUM> of the cell <NUM>-<NUM> and the first insulating material <NUM> of the cell <NUM>-<NUM> bond with each other and secure the electrical insulating property between the second part <NUM> of the positive electrode current collector <NUM> of the cell <NUM>-<NUM> and the second part <NUM> of the negative electrode current collector <NUM> of the cell <NUM>-<NUM>.

The stacked battery <NUM> shown in <FIG> is configured by the second part <NUM> of the positive electrode current collector <NUM> being wound over the first part <NUM> of the negative electrode current collector <NUM> via the second insulating material <NUM> and by the second part <NUM> of the negative electrode current collector <NUM> being wound over the first part <NUM> of the positive electrode current collector <NUM> via the first insulating material <NUM> so that the positive electrode current collector <NUM> contacts the positive electrode current collector <NUM> and the negative electrode current collector <NUM> contact the negative electrode current collector <NUM> at the time of stacking the cell <NUM>-<NUM> and the cell <NUM>-<NUM>.

The charging and discharging of the cell <NUM>-<NUM> and the cell <NUM>-<NUM> were evaluated under the following conditions:.

Using the stacked battery <NUM> including the cell <NUM>-<NUM> and the cell <NUM>-<NUM> stacked together, charging and discharging were performed under the following conditions:.

The respective CC (constant current) discharge capacities of the cell <NUM>-<NUM>, the cell <NUM>-<NUM>, and the stacked battery <NUM> became as shown in <FIG>. It was confirmed that parallel capacities (capacity of cell <NUM>-<NUM> + capacity of cell <NUM>-<NUM>) can be realized by simple stacking of the cell <NUM>-<NUM> and the cell <NUM>-<NUM>.

Claim 1:
A stacked battery comprising a stack of cells each having an electrode body including positive electrode current collector, positive electrode, electrolyte, negative electrode, and negative electrode current collector stacked in that order, a first insulating material arranged on an opposite side of the positive electrode across a first part of the positive electrode current collector, and a second insulating material arranged on an opposite side of the negative electrode across a first part of the negative electrode current collector, wherein
the positive electrode current collector has the first part of the positive electrode current collector, a second part of the positive electrode current collector, and a third part of the positive electrode current collector extending in a stacking direction of the cells and connecting the first part of the positive electrode current collector and the second part of the positive electrode current collector,
the second part of the positive electrode current collector is arranged on an opposite side of the first part of the negative electrode current collector across the second insulating material,
the negative electrode current collector has the first part of the negative electrode current collector, a second part of the negative electrode current collector, and a third part of the negative electrode current collector extending in the stacking direction and connecting the first part of the negative electrode current collector and the second part of the negative electrode current collector,
the second part of the negative electrode current collector is arranged on an opposite side from the first part of the positive electrode current collector across the first insulating material,
the first insulating material is arranged so as not to overlap both of the second insulating material and the second part of the positive electrode current collector in the stacking direction, and
the second part of the negative electrode current collector is arranged so as not to overlap both of the second insulating material and the second part of the positive electrode current collector in the stacking direction.