Patent Description:
<CIT> discloses as a conventional power storage unit, a technique to arrange power storages in longitudinal arrangement and horizontal arrangement as being mixed, each of the power storages having a ratio of a length between a long side and a short side of <NUM>:<NUM>. <CIT> discusses a platform for an electrical vehicle. <CIT> discusses an electric vehicle battery enclosure. <CIT> discusses a vehicle battery pack assembly.

In the power storage unit described in <CIT>, however, in a mount state, the power storages may be arranged in longitudinal arrangement on at least one side in a width direction of a vehicle. In an example in which the power storage unit thus includes power storages arranged in longitudinal arrangement on one side in the width direction, when a vehicle is hit broadside, insufficient durability of the power storage unit against side impact is a concern.

In <CIT>, when power storages aligned in a row direction are arranged in parallel to a front/rear direction of the vehicle, the power storages are arranged in horizontal arrangement on opposing sides in the width direction of the vehicle. In such arrangement, however, the power storages are arranged in horizontal arrangement in the entire width direction of the vehicle, and the power storages may not be arranged appropriately in correspondence with a vehicle width of a desired size.

The present disclosure was made in view of problems as above, and an object of the present disclosure is to provide a vehicle according to claim <NUM>, on which a power storage unit is mounted and can achieve improved durability against side impact applied to a vehicle, and a vehicle including the power storage unit.

A power storage unit based on the present disclosure includes power storages each including a pair of long side portions and a pair of short side portions in a plan view, each power storage being in a rectangular shape. The power storages include first power storages arranged on one side in a first direction in parallel to a width direction of a vehicle in a mount state in which the power storage unit is mounted on the vehicle, second power storages arranged on the other side in the first direction, and at least one third power storage arranged between the first power storages and the second power storages in the first direction. The first power storages and the second power storages are arranged in horizontal arrangement as being aligned in a second direction in parallel to a front/rear direction of the vehicle such that the short side portions are in parallel to the second direction and the long side portions are in parallel to the first direction in the mount state. The at least one third power storage is arranged in longitudinal arrangement such that the short side portions are in parallel to the first direction and the long side portions are in parallel to the second direction.

In the construction, the first power storages and the second power storages located on opposing sides in the first direction are arranged in horizontal arrangement as being aligned in the second direction such that the short side portions are in parallel to the second direction and the long side portions are in parallel to the first direction.

Therefore, when shock is applied by side impact, the long side portions arranged as being aligned in the second direction function as support wall portions.

When the first power storages and the second power storages are arranged in longitudinal arrangement as being aligned in the second direction, on the other hand, the short side portions arranged as being aligned in the second direction function as the support wall portions.

Therefore, when the first power storages and the second power storages are arranged in horizontal arrangement as being aligned in the second direction, the number of support wall portions can be larger than in an example in which they are arranged in longitudinal arrangement as being aligned in the second direction. Shock applied by side impact can thus be distributed to the support wall portions, and shock applied per one support wall portion can be lessened. Consequently, shock resistance of the power storage unit against side impact can be improved.

By arranging at least one third power storage in accordance with a vehicle width of a desired size, power storages can appropriately be arranged in correspondence with the vehicle width of the desired size.

In the power storage unit based on the present disclosure, n (n being an integer equal to or larger than two) first power storages and n second power storages may be arranged as being aligned in the second direction. In this case, of the long side portions included in the at least one third power storage, the long side portion located closest to the first power storages is preferably opposed to n short side portions aligned in the second direction on the other side in the first direction, of pairs of the short side portions included in the first power storages. Of the long side portions included in the at least one third power storage, the long side portion located closest to the second power storages is preferably opposed to n short side portions aligned in the second direction on the one side in the first direction, of pairs of the short side portions included in the second power storages.

In the construction, a space where the power storages are placed can effectively be made use of while shock resistance of the power storage unit against side impact is improved.

In the power storage unit based on the present disclosure, a ratio of a length between the short side portion and the long side portion may be set to <NUM>:n (n being an integer equal to or larger than two).

In the construction, the power storages can further efficiently be arranged and a space where the power storages are placed can be made smaller.

In the power storage unit based on the present disclosure, basic units each including the first power storages, the second power storages, and the at least one third power storage may be arranged as being aligned in the second direction.

In the construction, since basic units are arranged as being aligned in the second direction, a capacity of the power storage unit can be increased while durability against side impact is improved.

In the power storage unit based on the present disclosure, each of the power storages includes a positive electrode external terminal portion and a negative electrode external terminal portion. In this case, the first power storages and the second power storages may be identical in pattern of arrangement of the positive electrode external terminal portion and the negative electrode external terminal portion. The at least one third power storage may be different in pattern of arrangement of the positive electrode external terminal portion and the negative electrode external terminal portion from the first power storages and the second power storages.

In the construction, the power storages can be connected in series while types of power storages different in pattern of arrangement are fewer.

The power storage unit is mounted on a vehicle based on the present disclosure.

The present disclosure will be described in detail below with reference to the drawings. The same elements or elements in common in the embodiment shown below have the same reference characters allotted in the drawings and description thereof will not be repeated.

<FIG> is a diagram schematically showing a vehicle on which a power storage unit according to a first arrangement is mounted. A vehicle <NUM> on which a power storage unit <NUM> according to the first arrangement is mounted will be described with reference to <FIG>.

Vehicle <NUM> is a hybrid vehicle that can travel with motive power from at least one of a motor and an engine or an electrically powered vehicle that travels with driving force obtained from electric energy.

Vehicle <NUM> includes a front seat <NUM>, a rear seat <NUM>, a floor panel <NUM>, and power storage unit <NUM>.

Floor panel <NUM> forms a bottom of a main body of vehicle <NUM>. Front seat <NUM> and rear seat <NUM> are arranged in a compartment of vehicle <NUM>. Front seat <NUM> and rear seat <NUM> are arranged at a distance in a front/rear direction of the vehicle. Front seat <NUM> and rear seat <NUM> are arranged above floor panel <NUM>.

Power storage unit <NUM> is mounted on floor panel <NUM>. Power storage unit <NUM> is arranged below rear seat <NUM> and more specifically between rear seat <NUM> and floor panel <NUM>.

Power storage unit <NUM> supplies electric power to a motor for driving the vehicle. Electric power generated by the motor by regenerative braking or the like is stored in power storage unit <NUM>. Power storage unit <NUM> includes power storages <NUM> (see <FIG>).

<FIG> is a perspective view schematically showing the power storage provided in the power storage unit according to the first arrangement. <FIG> is a cross-sectional view along the line III-III shown in <FIG>. <FIG> is a perspective view schematically showing a power storage module, a conductive member, and the like provided in the power storage according to the first arrangement. Power storage <NUM> will be described with reference to <FIG>.

As shown in <FIG>, power storage <NUM> is substantially in a shape of a parallelepiped, and in a plan view, it is in a substantially rectangular shape including a longitudinal direction L and a short-side direction S. Power storage <NUM> includes a pair of long side portions <NUM> and a pair of short side portions <NUM> in the plan view. Power storage <NUM> includes a casing <NUM>, a positive electrode external terminal portion <NUM>, and a negative electrode external terminal portion <NUM>.

Casing <NUM> is formed substantially in a shape of a parallelepiped. Casing <NUM> includes a top plate <NUM>, a bottom plate <NUM>, sidewalls <NUM> and <NUM>, and end walls <NUM> and <NUM>. Sidewall <NUM> and sidewall <NUM> are disposed in short-side direction S and sidewall <NUM> and sidewall <NUM> are formed to extend in longitudinal direction L. End wall <NUM> and end wall <NUM> are disposed in longitudinal direction L and end wall <NUM> and end wall <NUM> are formed to extend in short-side direction S.

Positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> are provided on an upper surface of top plate <NUM>. Positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> are arranged at a distance in short-side direction S.

As shown in <FIG>, power storage <NUM> includes a power storage module <NUM>, conductive members <NUM> and <NUM> connected to power storage module <NUM>, expansion accommodation materials <NUM> and <NUM>, insulating members <NUM> and <NUM>, and an insulating film <NUM>.

Power storage module <NUM> includes power storage cells <NUM>, <NUM>, and <NUM> stacked in a direction of stack H and connection members <NUM> and <NUM>. The number of power storage cells included in power storage module <NUM> is not limited to three, and the number of power storage cells can be changed as appropriate to two or more or four or more.

Since power storage cells <NUM> and <NUM> are constructed substantially similarly to power storage cell <NUM>, description of power storage cell <NUM> will be given.

As shown in <FIG> and <FIG>, power storage cell <NUM> includes an electrode assembly <NUM>, a housing <NUM>, a positive electrode current collection plate <NUM>, and a negative electrode current collection plate <NUM>.

Housing <NUM> is formed from an aluminum laminate film or the like. Electrode assembly <NUM> and a not-shown electrolyte solution are accommodated in housing <NUM>.

Housing <NUM> includes an upper film 39A and a lower film 39B. Upper film 39A is arranged to cover electrode assembly <NUM> from above and lower film 39B is provided to cover electrode assembly <NUM> from below.

An outer peripheral portion of upper film 39A and an outer peripheral portion of lower film 39B are bonded to each other by a not-shown adhesive.

Electrode assembly <NUM> is formed into a shape of a parallelepiped. Electrode assembly <NUM> includes positive electrode sheets, separators, and negative electrode sheets stacked in direction of stack H. The separator is arranged between the positive electrode sheet and the negative electrode sheet.

The positive electrode sheet includes an aluminum foil and a positive electrode composite material layer formed on each of front and rear surfaces of the aluminum foil. The negative electrode sheet includes a copper foil and a negative electrode composite material layer formed on each of front and rear surfaces of the copper foil.

The aluminum foil that forms the positive electrode sheet is drawn to one side surface of electrode assembly <NUM> and the copper foil that forms the negative electrode sheet is drawn to the other side surface of electrode assembly <NUM>. One side surface and the other side surface are disposed in short-side direction S and formed to extend in longitudinal direction L.

Positive electrode current collection plate <NUM> is formed of aluminum or the like. Positive electrode current collection plate <NUM> is arranged on one side surface (one side in short-side direction S). Aluminum foils that form the positive electrode sheet are welded to positive electrode current collection plate <NUM>.

An adhesive <NUM> is formed on an upper surface of positive electrode current collection plate <NUM> and bonds upper film 39A and positive electrode current collection plate <NUM> with each other. An adhesive <NUM> is formed on a lower surface of positive electrode current collection plate <NUM> and bonds lower film 39B and positive electrode current collection plate <NUM> with each other. Adhesives <NUM> and <NUM> extend to the outside of housing <NUM> in short-side direction S.

Positive electrode current collection plate <NUM> protrudes outward relative to housing <NUM> and adhesives <NUM> and <NUM> on one side in short-side direction S. Positive electrode current collection plate <NUM> includes an exposed portion <NUM> exposed through housing <NUM> and adhesives <NUM> and <NUM>.

Negative electrode current collection plate <NUM> is formed of copper or the like. Negative electrode current collection plate <NUM> is arranged on the other side surface (the other side in short-side direction S). Copper foils that form the negative electrode sheet are welded to negative electrode current collection plate <NUM>.

An adhesive <NUM> is formed on an upper surface of negative electrode current collection plate <NUM> and bonds negative electrode current collection plate <NUM> and upper film 39A with each other. An adhesive <NUM> is formed on a lower surface of negative electrode current collection plate <NUM> and bonds negative electrode current collection plate <NUM> and lower film 39B with each other. Adhesives <NUM> and <NUM> extend to the outside of housing <NUM> in short-side direction S.

Negative electrode current collection plate <NUM> protrudes outward relative to housing <NUM> and adhesives <NUM> and <NUM> in short-side direction S and includes an exposed portion <NUM> exposed through housing <NUM> and adhesives <NUM> and <NUM>.

As shown in <FIG>, power storage cell <NUM> includes a positive electrode current collection plate <NUM>, a negative electrode current collection plate <NUM>, and a housing <NUM>, and an electrode assembly and an electrolyte solution are accommodated in housing <NUM>. Positive electrode current collection plate <NUM> includes an exposed portion <NUM> similarly to positive electrode current collection plate <NUM>. Negative electrode current collection plate <NUM> includes an exposed portion <NUM> similarly to negative electrode current collection plate <NUM>.

Power storage cell <NUM> includes a positive electrode current collection plate <NUM>, a negative electrode current collection plate <NUM>, and a housing <NUM>, and an electrode assembly and an electrolyte solution are accommodated in housing <NUM>. Positive electrode current collection plate <NUM> includes an exposed portion <NUM> similarly to positive electrode current collection plate <NUM>. Negative electrode current collection plate <NUM> includes an exposed portion <NUM> similarly to negative electrode current collection plate <NUM>.

Positive electrode current collection plate <NUM>, negative electrode current collection plate <NUM>, and positive electrode current collection plate <NUM> are disposed in direction of stack H. Similarly, negative electrode current collection plate <NUM>, positive electrode current collection plate <NUM>, and negative electrode current collection plate <NUM> are disposed in direction of stack H. In other words, power storage cells <NUM>, <NUM>, and <NUM> are stacked such that the positive electrode current collection plate and the negative electrode current collection plate are alternately aligned in direction of stack H.

Connection member <NUM> is arranged to connect exposed portion <NUM> of positive electrode current collection plate <NUM> and exposed portion <NUM> of negative electrode current collection plate <NUM> to each other. Connection member <NUM> is provided to connect exposed portion <NUM> of positive electrode current collection plate <NUM> and exposed portion <NUM> of negative electrode current collection plate <NUM> to each other.

Conductive member <NUM> is welded to an upper surface of exposed portion <NUM> of negative electrode current collection plate <NUM>. Conductive member <NUM> is welded to a lower surface of exposed portion <NUM> of positive electrode current collection plate <NUM>.

As shown in <FIG>, conductive member <NUM> includes a connection plate <NUM>, a vertical wall <NUM>, a base <NUM>, and a protrusion <NUM>. Connection plate <NUM> is welded to the upper surface of exposed portion <NUM>. Connection plate <NUM> is formed to extend in longitudinal direction L and protrudes toward end wall <NUM> relative to power storage module <NUM>. Connection plate <NUM> is arranged from one end to the other end of negative electrode current collection plate <NUM> in longitudinal direction L.

Vertical wall <NUM> is connected to an end of connection plate <NUM> located on a side of end wall <NUM>. Vertical wall <NUM> is formed to extend upward from the end of connection plate <NUM>.

Base <NUM> is formed at an upper end of vertical wall <NUM> and protrusion <NUM> is formed to protrude from base <NUM>. Protrusion <NUM> has an upper end connected to negative electrode external terminal portion <NUM> shown in <FIG>.

Conductive member <NUM> includes a connection plate <NUM>, a vertical wall <NUM>, a base <NUM>, and a protrusion <NUM>. Connection plate <NUM> is welded to a lower surface of exposed portion <NUM> of positive electrode current collection plate <NUM>. Connection plate <NUM> is formed to extend in longitudinal direction L and protrudes toward end wall <NUM> relative to power storage module <NUM>. Connection plate <NUM> is arranged from one end to the other end of positive electrode current collection plate <NUM> in longitudinal direction L.

Base <NUM> is formed at an upper end of vertical wall <NUM> and protrusion <NUM> is formed to protrude from base <NUM>. Protrusion <NUM> has an upper end connected to positive electrode external terminal portion <NUM> shown in <FIG>.

As shown in <FIG> again, expansion accommodation material <NUM> is arranged between an upper surface of power storage module <NUM> and top plate <NUM> of casing <NUM>. Expansion accommodation material <NUM> is arranged between a lower surface of power storage module <NUM> and bottom plate <NUM> of casing <NUM>. Expansion accommodation materials <NUM> and <NUM> each include a wrapping material and a dilatant material filled in the wrapping material.

Insulating member <NUM> is filled to reach power storage module <NUM> from sidewall <NUM>. Exposed portion <NUM> of positive electrode current collection plate <NUM>, exposed portion <NUM> of negative electrode current collection plate <NUM>, connection member <NUM>, and at least a part of conductive member <NUM> are located within insulating member <NUM>.

Insulating member <NUM> is filled to reach power storage module <NUM> from sidewall <NUM>. At least a part of conductive member <NUM>, exposed portion <NUM> of negative electrode current collection plate <NUM>, exposed portion <NUM> of positive electrode current collection plate <NUM>, and exposed portion <NUM> of negative electrode current collection plate <NUM> are located within insulating member <NUM>.

As power storage <NUM> constructed as above is charged or discharges, power storage module <NUM> deforms to expand in direction of stack H. At this time, expansion accommodation materials <NUM> and <NUM> deform to allow deformation of power storage module <NUM> as expanding. Thus, even when power storage module <NUM> deforms to expand, load applied to casing <NUM> through expansion accommodation materials <NUM> and <NUM> can be suppressed. Then, deformation of casing <NUM> can be suppressed.

When vehicle <NUM> travels, vibration may be applied to power storage <NUM>. For example, power storage <NUM> may vibrate in such a manner that an anti-node of vibration is located at the center in longitudinal direction L of power storage <NUM>.

At this time, a rate of displacement of a central portion of power storage <NUM> is higher than a rate of expansion of power storage module <NUM> in charging and discharging. Since expansion accommodation materials <NUM> and <NUM> include the dilatant material, rigidity against deformation at a high speed is high. Therefore, expansion accommodation materials <NUM> and <NUM> are less likely to deform and vibration of power storage <NUM> is suppressed.

In charging and discharging of power storage <NUM>, a temperature of power storage module <NUM> increases. At this time, insulating member <NUM> is formed to cover exposed portions <NUM>, <NUM>, and <NUM>, connection member <NUM>, and at least a part of conductive member <NUM>. Since exposed portions <NUM>, <NUM>, and <NUM>, connection member <NUM>, and conductive member <NUM> are formed of a metal material, heat in power storage module <NUM> is satisfactorily radiated to insulating member <NUM>. Heat transmitted to insulating member <NUM> is radiated from sidewall <NUM>.

Insulating member <NUM> is formed to cover at least a part of conductive member <NUM>, exposed portions <NUM>, <NUM>, and <NUM>, and connection member <NUM>. Since conductive member <NUM>, exposed portions <NUM>, <NUM>, and <NUM>, and connection member <NUM> are formed of a metal material, heat in power storage module <NUM> is satisfactorily radiated to insulating member <NUM>. Heat transmitted to insulating member <NUM> is radiated from sidewall <NUM>. Power storage module <NUM> can thus satisfactorily be cooled.

As described above, in <FIG>, connection plate <NUM> of conductive member <NUM> is connected to negative electrode current collection plate <NUM> and formed to extend in longitudinal direction L. In longitudinal direction L, connection plate <NUM> is formed from one end to the other end of negative electrode current collection plate <NUM>.

Therefore, when negative electrode external terminal portion <NUM> is provided on the side of end wall <NUM> as in the present arrangement, connection to negative electrode external terminal portion <NUM> can easily be established by connecting vertical wall <NUM> or the like to the end of connection plate <NUM> on the side of end wall <NUM>.

Similarly, connection plate <NUM> of conductive member <NUM> is formed to extend in longitudinal direction L. Then, in longitudinal direction L, connection plate <NUM> is arranged from one end to the other end of negative electrode current collection plate <NUM>.

Therefore, when positive electrode external terminal portion <NUM> is provided on the side of end wall <NUM> as in the present arrangement, connection to positive electrode external terminal portion <NUM> can easily be established by connecting vertical wall <NUM> or the like to the end of connection plate <NUM> on the side of end wall <NUM>.

<FIG> is a top view of the power storage unit according to the first arrangement. Power storage unit <NUM> according to the first arrangement will be described with reference to <FIG>.

Power storage unit <NUM> includes power storages <NUM> and bus bars <NUM>. Power storages <NUM> include first power storages <NUM>, second power storages <NUM>, and a third power storage <NUM>.

First power storages <NUM> are arranged on one side in a first direction DR1. First direction DR1 is in parallel to a width direction of a vehicle in a mount state in which power storage unit <NUM> is mounted on vehicle <NUM>.

First power storages <NUM> are arranged as being aligned in a second direction DR2. Second direction DR2 is a direction orthogonal to first direction DR1 and in parallel to the front/rear direction of the vehicle in the mount state.

Each of first power storages <NUM> is arranged in horizontal arrangement such that short side portion <NUM> is in parallel to second direction DR2 and long side portion <NUM> is in parallel to first direction DR1. In the first arrangement, two first power storages <NUM> are arranged in horizontal arrangement as being aligned in second direction DR2.

Second power storages <NUM> are arranged on the other side in first direction DR1. Each of second power storages <NUM> is arranged in horizontal arrangement such that short side portion <NUM> is in parallel to second direction DR2 and long side portion <NUM> is in parallel to first direction DR1. In the first arrangement, two second power storages <NUM> as many as first power storages <NUM> are arranged in horizontal arrangement as being aligned in second direction DR2.

Third power storage <NUM> is arranged between first power storages <NUM> and second power storages <NUM> in first direction DR1. Third power storage <NUM> is arranged in longitudinal arrangement such that short side portion <NUM> is in parallel to first direction DR1 and long side portion <NUM> is in parallel to second direction DR2.

Of long side portions <NUM> included in third power storage <NUM>, long side portion <NUM> located closest to first power storages <NUM> is opposed to two short side portions <NUM> aligned in second direction DR2 on the other side in first direction DR1, of pairs of short side portions <NUM> included in first power storages <NUM>.

Of the long side portions included in third power storage <NUM>, long side portion <NUM> located closest to second power storages <NUM> is opposed to two short side portions <NUM> aligned in second direction DR2 on one side in first direction DR1, of pairs of short side portions <NUM> included in second power storages <NUM>.

By thus arranging third power storage <NUM>, a space where power storages <NUM> are placed can effectively be made use of.

As described above, when two first power storages <NUM> and two second power storages <NUM> are arranged as being aligned in the second direction, a ratio of a length between short side portion <NUM> and long side portion <NUM> is set preferably to <NUM>:<NUM>. By setting such a length ratio, power storages <NUM> can further efficiently be arranged and the space where power storages are placed can be made smaller.

Each of bus bars <NUM> connects negative electrode external terminal portion <NUM> and positive electrode external terminal portion <NUM> in adjacent power storages <NUM> to each other. Power storages <NUM> are thus connected in series.

Second power storage <NUM> is the same as first power storage <NUM> arranged as being turned by <NUM> degrees, and first power storages <NUM> and second power storages <NUM> are identical in pattern of arrangement of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM>.

Third power storage <NUM> is not in rotation symmetry to first power storage <NUM> and second power storage <NUM>, and positions of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> in third power storage <NUM> are opposite to positions of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> in first power storage <NUM> and second power storage <NUM>. In other words, third power storage <NUM> is different in pattern of arrangement of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> from first power storage <NUM> and second power storage <NUM>.

Specifically, in first power storage <NUM> and second power storage <NUM>, when first power storage <NUM> and second power storage <NUM> are arranged such that positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> are located on the other side in first direction DR1, positive electrode external terminal portion <NUM> is arranged on one side in second direction DR2 and negative electrode external terminal portion <NUM> is arranged on the other side in second direction DR2.

In third power storage <NUM>, on the other hand, when third power storage <NUM> is arranged such that positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> are located on the other side in first direction DR1, negative electrode external terminal portion <NUM> is arranged on one side in second direction DR2 and positive electrode external terminal portion <NUM> is arranged on the other side in second direction DR2.

By setting the pattern of arrangement of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> in first power storage <NUM>, second power storage <NUM>, and third power storage <NUM> as above, power storages <NUM> can be connected in series while types of the power storages different in pattern of arrangement are fewer.

When vehicle <NUM> is hit broadside with power storage unit <NUM> being mounted on vehicle <NUM>, shock is applied from the side of first power storages <NUM> or second power storages <NUM>.

First power storages <NUM> and second power storages <NUM> are arranged in horizontal arrangement as being aligned in second direction DR2 such that short side portion <NUM> is in parallel to second direction DR2 and long side portion <NUM> is in parallel to first direction DR1 as described above.

Therefore, when shock is applied by side impact, long side portions <NUM> arranged as being aligned in second direction DR2 function as support wall portions.

When first power storages <NUM> and second power storages <NUM> are arranged as being aligned in second direction DR2 in longitudinal arrangement, short side portions <NUM> arranged as being aligned in second direction DR2 function as the support wall portions.

Therefore, when first power storages <NUM> and second power storages <NUM> are arranged as being aligned in second direction DR2 in horizontal arrangement, a larger number of support wall portions can be provided than in an example where first power storages <NUM> and second power storages <NUM> are arranged in longitudinal arrangement as being aligned in second direction DR2. Shock applied by side impact can thus be distributed to support wall portions, and shock applied per one support wall portion can be lessened. Consequently, shock resistance of power storage unit <NUM> against side impact can be improved.

In the present arrangement, a single third power storage <NUM> is provided, so that power storage unit <NUM> can suitably be mounted, for example, on a vehicle having a vehicle width approximately not larger than <NUM>.

The number of third power storages <NUM> should only be set to at least one. Therefore, by changing as appropriate the number in accordance with the vehicle width, power storages can appropriately be arranged in correspondence with the vehicle width of a desired size.

<FIG> is a top view of a power storage unit according to a second arrangement. A power storage unit 200A according to the second arrangement will be described with reference to <FIG>.

As shown in <FIG>, power storage unit 200A according to the second arrangement is different in number of third power storages <NUM> from power storage unit <NUM> according to the first arrangement. Specifically, three third power storages <NUM> are provided. The construction is otherwise substantially similar.

According to such a construction as well, power storage unit 200A according to the second embodiment achieves an effect substantially similar to the effect of power storage unit <NUM> according to the first arrangement. Power storage unit 200A according to the second arrangement can suitably be mounted on vehicle <NUM> larger in vehicle width than in the first arrangement. Specifically, power storage unit 200A can suitably be mounted, for example, on vehicle <NUM> having a vehicle width approximately not larger than <NUM>.

<FIG> is a top view of a power storage unit according to a third arrangement. A power storage unit 200B according to the third arrangement will be described with reference to <FIG>.

As shown in <FIG>, power storage unit 200B according to the third arrangement is different from power storage unit <NUM> according to the first arrangement in that sizes thereof in first direction DR1 and second direction DR2 are larger and power storage unit 200B is arranged below floor panel <NUM>. The construction is otherwise substantially similar.

In this case, basic units <NUM> each composed of two first power storages <NUM>, two second power storages <NUM>, and one third power storage <NUM> shown in the first arrangement are arranged as being aligned in second direction DR2. Specifically, four basic units <NUM> are arranged as being aligned in second direction DR2.

In this case as well, as in the first arrangement, third power storage <NUM> is different in pattern of arrangement of positive electrode external terminal portion <NUM> and negative electrode external terminal portion <NUM> from first power storage <NUM> and second power storage <NUM>.

According to such a construction as well, power storage unit 200B according to the third embodiment achieves an effect substantially similar to the effect of power storage unit <NUM> according to the first arrangement,.

Since basic units <NUM> are arranged as being aligned in second direction DR2, a capacity of power storage unit 200B can be increased while durability against side impact is improved.

An example in which two first power storages <NUM> and two second power storages <NUM> are arranged as being aligned in second direction DR2 in the first and second arrangements and in basic unit <NUM> in the third arrangement is illustrated and described. Without being limited as such, at least n (n being an integer equal to or larger than two) first power storages <NUM> and at least n second power storages <NUM> may be provided.

In this case, of long side portions <NUM> included in at least one third power storage <NUM>, long side portion <NUM> located closest to first power storages <NUM> may be opposed to n short side portions <NUM> aligned in second direction DR2 on the other side in first direction DR1, of pairs of short side portions <NUM> included in first power storages <NUM>, and of long side portions <NUM> included in at least one third power storage <NUM>, long side portion <NUM> located closest to second power storages <NUM> may be opposed to n short side portions <NUM> aligned in second direction DR2 on one side in first direction DR1, of pairs of short side portions <NUM> included in second power storages <NUM>.

The ratio of the length between short side portion <NUM> and long side portion <NUM> may be set to <NUM>:n (n being an integer equal to or larger than two). Power storages <NUM> can thus efficiently be arranged.

Claim 1:
A vehicle (<NUM>) comprising:
a power storage unit (<NUM>, 200A, 200B) mounted on the vehicle (<NUM>), the power storage unit (<NUM>, 200A, 200B) comprising:
power storages (<NUM>) each including a pair of long side portions (<NUM>) and a pair of short side portions (<NUM>) in a plan view, each power storage being in a rectangular shape, wherein
the power storages (<NUM>) include first power storages (<NUM>) arranged on one side in a first direction (DR1) in parallel to a width direction of the vehicle in a mount state in which the power storage unit is mounted on the vehicle, second power storages (<NUM>) arranged on the other side in the first direction (DR1), and at least one third power storage (<NUM>) arranged between the first power storages (<NUM>) and the second power storages (<NUM>) in the first direction (DR1), wherein the number of first power storages (<NUM>) is the same as the number of second power storages (<NUM>), and the first power storages (<NUM>) are the same as the second power storages (<NUM>),
the first power storages (<NUM>) and the second power storages (<NUM>) are arranged in horizontal arrangement as being aligned in a second direction (DR2) in parallel to a front/rear direction of the vehicle such that the short side portions (<NUM>) are in parallel to the second direction (DR2) and the long side portions (<NUM>) are in parallel to the first direction (DR1) in the mount state, and
the at least one third power storage (<NUM>) is arranged in longitudinal arrangement such that the short side portions (<NUM>) are in parallel to the first direction (DR1) and the long side portions (<NUM>) are in parallel to the second direction (DR2).