JP2008103268A - Battery pack and vehicle - Google Patents

Abstract

To provide an assembled battery that can be directly or indirectly attached to a vehicle body of a vehicle and that can suppress internal resistance and increase output, and a vehicle equipped with such an assembled battery.
An assembled battery includes a plurality of single cells. Each unit cell 100 includes a power generation element having a positive electrode plate, a negative electrode plate, and a separator, and an electrolytic solution. The power generation element includes an electrode overlap portion, a positive electrode plate terminal portion 171 in which only the positive electrode plate extends from the electrode overlap portion, and a negative electrode plate terminal portion 172 in which only the negative electrode plate extends from the electrode overlap portion. ,including. In the state in which the assembled battery 10 is attached to the vehicle body, the plurality of single cells 100 have a positive electrode plate terminal portion that is relatively hot among the positive electrode plate terminal portion and the negative electrode plate terminal portion than the negative electrode plate terminal portion. It is arranged in a posture that is vertically downward.
[Selection] Figure 3

Description

  The present invention relates to an assembled battery that is directly or indirectly attached to a vehicle body of a vehicle and a vehicle equipped with the assembled battery.

  In recent years, an assembled battery composed of a plurality of unit cells, for example, temporarily stores surplus power during nighttime by charging, and in addition to a power storage device that uses the stored power by discharging, an electric vehicle, It is used as a power source for driving a vehicle such as a hybrid car (see, for example, Patent Document 1).

JP 2001-243975 A

  A module (assembled battery) disclosed in Patent Document 1 includes a plurality of sodium-sulfur batteries (unit cells) having a substantially cylindrical shape, a bottomed box-shaped storage container having a heat insulation effect, and a lid member for closing the container And a heater provided at the bottom of the storage container, and a flat insulating plate. The sodium-sulfur battery is filled with a positive electrode active material such as sulfur or sodium polysulfide and sodium. In this module, a plurality of sodium-sulfur batteries are housed in a storage container via an insulating plate disposed on the heater, and the opening of the storage container is closed with a lid member. Adjacent sodium-sulfur batteries are connected by a bus bar. In this module, the lower part of each sodium-sulfur battery is heated with a heater, and the temperature of the lower part is made higher than that of the upper part to promote convection of the positive electrode active material. Thereby, reduction of internal resistance in each sodium sulfur battery is aimed at.

In such an assembled battery, the power generation element generates heat by battery reaction (electrochemical reaction) during charging or discharging inside each unit cell. However, since the power generation element has a relatively high temperature portion and a relatively low temperature portion, there is a variation in each part with respect to the ease of battery reaction. As a result, the unit resistance of the unit cell is large. turn into.
By the way, when an assembled battery is used as a power source for driving a vehicle, it is required to reduce the size of the assembled battery as much as possible and to reduce its weight and cost. On the other hand, since a relatively large output is required for driving the vehicle, an assembled battery that can obtain a battery output as large as possible is required.
On the other hand, in the assembled battery described in Patent Document 1, the internal resistance of each unit cell can be reduced by convection of the positive electrode active material, and the cell characteristics of each unit cell can be improved. Since the temperature is raised, an installation space for the heater and electric energy for heating the heater are required.

  The present invention has been made in view of the present situation, and in an assembled battery that is directly or indirectly attached to a vehicle body, an assembled battery that can suppress internal resistance and increase output, and such an assembled battery are mounted. An object is to provide a vehicle.

  The solution is an assembled battery that has a plurality of single cells and is directly or indirectly attached to a vehicle body, and each of the single cells includes a power generation element having a positive electrode plate, a negative electrode plate, and a separator, and an electrolytic solution. And the power generation element includes an electrode overlap portion in which the positive electrode plate and the negative electrode plate are overlapped via the separator, and only the positive electrode plate is the positive electrode plate, the negative electrode plate, and the separator. A positive electrode plate terminal portion extending from the electrode overlap portion, and disposed on the opposite side of the positive electrode plate terminal portion via the electrode overlap portion, and among the positive electrode plate, the negative electrode plate and the separator, the negative electrode plate And a negative plate terminal portion formed only by extending from the electrode overlap portion, and the unit cell is arranged so that the negative plate terminal portion is at the same height in the vertical direction with respect to the positive plate terminal portion. Place, charge or release Of the positive electrode plate terminal portion and the negative electrode plate terminal portion, when the relatively high temperature is the high temperature side terminal portion and the low temperature side is the low temperature side terminal portion, the assembled battery is In the state of being attached to the vehicle body, each of the plurality of single cells is an assembled battery in which the high temperature side terminal portion is arranged in a posture that is vertically lower than the low temperature side terminal portion.

  First, consider each single cell in the above-described posture. In the unit cell having this posture, the temperature of the lower high temperature side terminal portion becomes higher during charging or discharging, so that the electrolyte below is directed upward by convection, and conversely, Moves downward. Along with this, heat transfer occurs inside the unit cell. For this reason, the temperature difference of each part in an electrode overlapping part is compared with the case where the said cell is arrange | positioned in the attitude | position in which the electrode overlapping part, a positive electrode plate terminal part, and a negative electrode plate terminal part become the same height in a perpendicular direction. Can be suppressed. Thus, the internal resistance of the unit cell can be further reduced. Therefore, for any single battery, the assembled battery of the present invention having such an attitude can have a low internal resistance, a large output, and a good characteristic as the assembled battery as a whole.

  As described above, by setting each unit cell to the above-described posture, in the assembled battery of the present invention, among the plurality of unit cells, only a part of the unit cells has a higher temperature side terminal portion than a lower temperature side terminal portion. The characteristics of the assembled battery as a whole can be further improved as compared with the case where it is disposed in a posture that is vertically downward.

Examples of the assembled battery include assembled batteries in which a plurality of single cells are connected in series to each other, and assembled batteries in which parallel, parallel series, and series-parallel are connected.
In addition, as the power generation element, there are a plurality of plate-like positive electrode plates, negative electrode plates, and separators, and a stacked power generation element in which positive electrode plates and negative electrode plates are alternately laminated via separators, or a belt-like positive electrode plate In addition, a wound-type power generation element obtained by winding a positive electrode plate and a negative electrode plate through a separator using a negative electrode plate and a separator can be mentioned.
Examples of vehicles include electric vehicles and hybrid cars, as well as vehicles such as forklifts, electric wheelchairs, electric assist bicycles, and electric scooters.

  Furthermore, it is an assembled battery of Claim 1, Comprising: The said unit cell is lithium which used lithium oxide for the positive electrode active material which the said positive electrode plate carry | supported, and carbon for the negative electrode active material which the said negative electrode plate carry | supported. It is an ion secondary battery, and it is good to set it as the assembled battery whose said high temperature side terminal part is the said positive electrode plate terminal part.

In the assembled battery of the present invention, since the lithium ion secondary battery is used as a single battery, it is small and lightweight, and a relatively large output can be obtained.
In addition, since any single battery is in the above-described posture, the internal resistance can be lowered, and the characteristics of the entire assembled battery can be improved.

  Another solution is a vehicle on which the assembled battery according to claim 1 or 2 is mounted.

  In the vehicle of the present invention, an assembled battery having a low internal resistance is mounted on any single battery, so that better running performance can be obtained using this assembled battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the vehicle 1 according to the present embodiment is a hybrid car that is driven by the combined use of an engine 3, a front motor 4, and a rear motor 5. The vehicle 1 includes a vehicle body 2, an engine 3, a front motor 4, a rear motor 5, a cable 7, and a battery pack 6 attached thereto. As shown in FIGS. 1 and 2, the battery pack 6 is attached to the vehicle body 2 of the vehicle 1. The battery pack 6 contains a battery pack 10 to be described later. The assembled battery 10 is connected to the front motor 4 and the rear motor 5 by a cable 7. The vehicle 1 can be driven by the engine 3, the front motor 4 and the rear motor 5 by a known means using the assembled battery 10 as a driving power source for the front motor 4 and the rear motor 5.

  In the vehicle 1, the assembled battery 10 according to this embodiment includes a battery module 11 in which a plurality of single cells 100 are arranged in a line and electrically connected in series by a bus bar 200 as shown in FIGS. 2 and 3. (11A and 11B) are arranged in a plurality (two are shown in FIG. 2). As shown in FIG. 4, the unit cell 100 is a lithium ion secondary battery of a rectangular unit cell having a substantially rectangular parallelepiped shape.

The single battery 100 will be described.
The unit cell 100 includes a case member 150 having a rectangular parallelepiped shape, a sealing member 160 that closes the case member 150, a power generation element 110 housed in the case member 150, and an electrolyte LQ. An electrolytic solution LQ is injected into the unit cell 100. In the unit cell 100, the case member 150 is made of metal. As shown in FIGS. 4 to 6, the plate side rectangular first side 151 and the second side 152 having the same shape in parallel with the first side 151 are provided. Have. The case member 150 includes a flat rectangular third side portion 153 and a fourth side portion that connect the short side of the first side portion 151 (the vertical side in FIG. 4) and the short side of the second side portion 152. 154. The case member 150 also has a flat rectangular bottom 155 that connects the long side of the first side 151 (the side in the lower left-upper right direction in FIG. 4) and the long side of the second side 152. Further, the case member 150 has an accommodating portion 156 that opens on the insertion side (upward in FIG. 5) and accommodates the power generation element 110 inserted from the opening.

  The sealing member 160 is made of metal and has a long side along the first side 151 and the second side 152 in the case member 150 and a short side along the third side 153 and the fourth side 154 (FIG. 6). The side plate is a rectangular flat plate. The sealing member 160 is configured to liquid-tightly close the opening of the case member 150 after the power generation element 110 is accommodated in the accommodating portion 156 of the case member 150.

  Further, the sealing member 160 includes a positive terminal insertion hole 161H and a negative terminal insertion hole 162H that are spaced apart at a predetermined interval in a direction along the long side of the first side portion 151 (lower left-upper right direction in FIG. 4), A valve hole 163H penetrating the inside and the outside is provided at a position between them. The valve hole 163H is closed by a plate-shaped safety valve 190.

  The power generation element 110 includes a positive electrode plate 121 made of aluminum, a negative electrode plate 122 made of copper, and a separator 123, all of which are band-shaped. The positive electrode plate 121 and the negative electrode plate 122 are wound around the separator 123. As shown in FIGS. 5 and 6, the power generation element 110 includes an electrode overlapping portion 113, a positive plate terminal portion 111, and a negative plate terminal portion 112. Among these, the electrode overlapping portion 113 is a portion where the positive electrode plate 121, the negative electrode plate 122, and the separator 123 are overlapped. On the other hand, in the positive electrode plate terminal portion 111, only the positive electrode plate 121 out of the positive electrode plate 121, the negative electrode plate 122, and the separator 123 is one side in the direction along the axis 110X of the power generation element 110 indicated by a one-dot chain line in FIG. This is a portion extending from the electrode overlapping portion 113 to the right in FIG. 5 and being spirally stacked. On the other hand, among the positive electrode plate 121, the negative electrode plate 122, and the separator 123, the negative electrode plate terminal portion 112 includes only the negative electrode plate 122 from the electrode overlapping portion 113 on the other side in the direction along the axis 110X (left side in FIG. 5). It is the site | part extended and spirally piled up.

  In the power generation element 110, for example, a lithium oxide such as lithium manganate is used as the positive electrode active material supported by the positive electrode plate 121 in the electrode overlapping portion 113. On the other hand, carbon is used for the negative electrode active material carried by the negative electrode plate 122.

  As shown in FIGS. 5 and 6, a part of the positive electrode plate terminal portion 111 of the power generation element 110 is compressed in the thickness direction of the power generation element 110 (left and right direction in FIG. 6) and overlaps with each other without a gap. Part 111C. A positive electrode current collecting member 173 connected to the external positive electrode terminal 171 is welded to the positive electrode fixing portion 111C. Thereby, the positive electrode plate 121 can be electrically connected to the external positive electrode terminal 171 through the positive electrode fixing portion 111C and the positive electrode current collecting member 173. Similarly, a part of the negative electrode plate terminal portion 112 is also a negative electrode fixing portion 112 </ b> C that is compressed in the thickness direction of the power generation element 110 and overlaps each other without a gap. A negative electrode current collecting member 174 connected to the external negative electrode terminal 172 is welded to the negative electrode fixing portion 112C. Thereby, the negative electrode plate 122 can be electrically connected to the external negative electrode terminal 172 via the negative electrode fixing portion 112 </ b> C and the negative electrode current collecting member 174.

The external positive electrode terminal 171 connected to the positive electrode terminal portion 111 of the power generation element 110 (positive electrode plate 121) is made of aluminum and has a flat plate shape. As shown in FIG. 5, the external positive terminal 171 protrudes outside the sealing member 160 through the positive terminal insertion hole 161 </ b> H of the sealing member 160. The external positive terminal 171 is liquid-tightly sealed by the positive seal member 181 molded in the positive terminal insertion hole 161H of the sealing member 160, and is electrically insulated from the sealing member 160.
On the other hand, the external negative electrode terminal 172 connected to the negative electrode terminal portion 112 of the power generation element 110 (negative electrode 122) is made of copper and has a flat plate shape. Similarly, the external negative electrode terminal 172 protrudes outside the sealing member 160 through the negative electrode terminal insertion hole 162H of the sealing member 160. The external negative electrode terminal 172 is also liquid-tightly sealed by the negative electrode sealing member 182 molded in the negative electrode terminal insertion hole 162H of the sealing member 160, and is electrically insulated from the sealing member 160.

  In the unit cell 100, an organic electrolyte is used as the electrolyte LQ. The electrolytic solution LQ is injected into the housing portion 156 of the case member 150 closed by the sealing member 160 so that a battery reaction (electrochemical reaction) with the electrode overlapping portion 113 of the power generation element 110 can be performed.

Next, the assembled battery 10 including a plurality of unit cells 100 will be described with reference to FIGS. 2 and 3.
In the present embodiment, as described above, in the assembled battery 10, a plurality of battery modules 11 (11A, 11B) in which a plurality of cells 100 are arranged in a line and electrically connected in series by a bus bar 200 are arranged. It becomes the composition. The assembled battery 10 is in a state in which the assembled battery 10 is attached to the vehicle body 2 of the vehicle 1, and any single battery 100 has the third side portion 153 of the case member 150 vertically downward (see FIG. 2 and FIG. 2). In FIG. 3, the external positive terminal 171 (positive plate terminal portion 111) is positioned lower than the external negative terminal 172 (negative plate terminal portion 112).

As shown in FIGS. 2 and 3, the unit cells 100, 100 arranged adjacent to each other include an external positive terminal 171 of one unit cell 100 and an external negative terminal 172 of another unit cell 100. Are connected by a bus bar 200 for electrically connecting them. Thereby, the plurality of single cells 100, 100 constituting each battery module 11 (11A, 11B) are all connected in series.
In addition, although not shown in figure, all the some battery modules 11 (11A, 11B) which comprise this assembled battery 10 are electrically connected in series.

By the way, the unit cell 100 according to the present embodiment is arranged such that the negative electrode plate terminal portion 112 is at the same height in the vertical direction with respect to the positive electrode plate terminal portion 111 (see FIG. 5), and is charged or discharged. When the positive electrode plate terminal portion 111 and the negative electrode plate terminal portion 112 are compared, the positive electrode plate terminal portion 111 has a relatively higher temperature than the negative electrode plate terminal portion 112. In the battery reaction (electrochemical reaction) between the electrolyte LQ and the positive electrode active material (lithium oxide) of the positive electrode plate 121 and the negative electrode active material (carbon) of the negative electrode plate 122 during charging or discharging of the unit cell 100, the positive electrode The reaction resistance on the side is higher and heat is relatively easily generated. For this reason, it is considered that the positive electrode plate 121, and hence the positive electrode plate terminal portion 111 that is a part of the positive electrode plate 121, has a higher temperature than the negative electrode plate terminal portion 112.
Therefore, in the present embodiment, the positive plate terminal portion 111 is also referred to as a high temperature side terminal portion. On the other hand, the negative electrode plate terminal portion 112 is also referred to as a low temperature side terminal portion.

  On the other hand, in the assembled battery 10, all of the single cells 100 constituting them are in the posture in which the assembled battery 10 is attached to the vehicle body 2 of the vehicle 1, as described above. ) Higher temperature side terminal portion (positive electrode plate terminal portion 111) is arranged in a posture that is vertically downward.

Since each unit cell 100 is arranged in such a posture, in each unit cell 100, the positive electrode plate terminal part 111 (high temperature side terminal part) that is relatively high temperature is located below, so that the positive electrode plate Convection occurs in which the lower electrolyte solution LQ heated by the terminal portion 111 moves upward, and conversely, the upper electrolyte solution LQ moves downward. Thereby, heat transfer occurs inside the single cell 100 (power generation element 110).
For this reason, when the unit cell 100 is arranged in a posture in which the electrode overlapping portion 113, the positive plate terminal portion 111, and the negative plate terminal portion 112 are at the same height in the vertical direction, that is, the posture of the single cell 100 shown in FIG. As compared with the above, it is possible to suppress the difference in temperature between the respective portions in the electrode overlapping portion 113. Thus, the battery reaction occurring in the electrode overlap portion 113 can be made uniform, and the internal resistance in the unit cell 100 can be further reduced. Therefore, the assembled battery 10 as a whole can have a low internal resistance, a large output, and a good assembled battery 10 with good characteristics.
In addition, in the assembled battery 10 according to the present embodiment, by setting all the unit cells 100 constituting the assembled battery 10 to the above-described posture, only a part of the unit cells 100 in the assembled battery 10 is a negative electrode. It is possible to further improve the characteristics of the assembled battery 10 as a whole, compared to the case where the positive electrode plate terminal portion 111 (high temperature side terminal portion) is arranged in a vertically lower direction than the plate terminal portion 112 (low temperature side terminal portion). is made of.

  Further, in the battery pack 10 according to the present embodiment, since the lithium ion secondary battery is used as the single battery 100, it is small and lightweight, and a relatively large output can be obtained.

  Thus, in the vehicle 1 according to the present embodiment, all the unit cells 100 of the assembled battery 10 included in the battery pack 6 are the unit cells 100 having a low internal resistance described above. Good running performance can be obtained.

Here, the posture of the unit cell 100 and the posture in which the negative electrode plate terminal portion 112 has the same height in the vertical direction with respect to its own positive electrode plate terminal portion 111 (see FIG. 5 and FIG. A first investigation is made on the temperature change of each of the positive electrode plate terminal portion 111, the negative electrode plate terminal portion 112, and the electrode overlap portion 113 when the unit cell 100 of “position A” is repeatedly charged and discharged. Went.
In this investigation, the unit cell 100 is placed in the posture A, the unit cell 100 is repeatedly charged and discharged, and the positive plate terminal portion 111, the negative plate terminal portion 112, and the electrode overlap portion 113 are contacted from the outside of the single cell 100 without contact. The temperature immediately after charging / discharging of the site | part corresponding to was measured.
In this survey, a commercially available infrared radiation thermometer (not shown) was used to measure the temperature. In the measurement, the unit cell 100 and the infrared radiation thermometer arranged in the posture A were accommodated in a thermostatic bath at 25 ° C., and charging / discharging with a 2 C current was repeated 30 times. Further, as shown in FIG. 7A, the measurement is performed in the first side portion 151 of the unit cell 100, the positive electrode side measuring portion 151 </ b> P close to the positive electrode plate terminal portion 111, and the negative electrode close to the negative electrode plate terminal portion 112. The side measurement part 151N and the electrode overlap part side measurement part 151C close to the electrode overlap part 113 were used.

The result of the first investigation is shown in FIG. According to FIG. 8, when the unit cell 100 is in the posture A, the positive electrode plate terminal portion 111 (positive electrode side measuring portion 151P), the negative electrode plate terminal portion 112 (negative electrode side measuring portion 151N), and the electrode overlapping portion 113 (electrode) In the overlap portion side measurement portion 151C), the temperature rises with an increase in the frequency of charge / discharge (number of cycles). Of these, the magnitude of the rise is the highest in the electrode overlap portion side measurement portion 151C. It is large, and it turns out that it is the order of the positive electrode side measurement part 151P and the negative electrode side measurement part 151N next to this.
The reason for this is considered as follows. That is, when the unit cell 100 is charged or discharged, two types of battery reactions (electrochemistry) between the electrolyte LQ and the positive electrode active material (lithium oxide) of the positive electrode plate 121 and the negative electrode active material (carbon) of the negative electrode plate 122. In comparison, the battery reaction between the electrolytic solution LQ and the positive electrode active material is relatively less likely to react and the reaction resistance is larger than the battery reaction between the electrolytic solution LQ and the negative electrode active material. . For this reason, the heat generation in the positive electrode active material is relatively greater than the heat generation in the negative electrode active material. For this reason, it is considered that the temperature rise in the positive electrode plate terminal portion 111 is larger than that in the negative electrode plate terminal portion 112.
In the electrode overlap portion 113, the positive electrode plate 121, the negative electrode plate 122, and the separator 123 are overlapped. For this reason, when the two types of battery reactions described above occur in the electrode overlap portion 113, the reaction heat generated at this time is stored in the electrode overlap portion 113, and as a result, the temperature rise in the electrode overlap portion 113 is the most. It seems that it has grown.
Thus, when the unit cell 100 is arranged in the posture A shown in FIG. 7A, when the positive plate terminal portion 111 and the negative plate terminal portion 112 are compared when charged or discharged, the positive plate terminal portion 111 is negative. It was confirmed that the temperature was relatively higher than that of the plate terminal portion 112.

Next, a second investigation was performed on the relationship between the position of the unit cell 100 (position of the positive electrode terminal portion 111 and the negative electrode terminal portion 112), the internal resistance, and the battery output when being attached to the vehicle body 2.
In the second investigation, as shown in FIG. 7, the unit cell 100 is placed in the above-described posture A in a constant temperature bath at a temperature of 25 ° C., and at a higher temperature than the low temperature side terminal portion (negative electrode plate terminal portion 112). The side terminal portion (positive electrode plate terminal portion 111) is in a posture B in which the lower side in the vertical direction is lower, and the high temperature side terminal portion (positive electrode plate terminal portion 111) is in the vertical direction higher than the low temperature side terminal portion (negative electrode plate terminal portion 112). In the posture C to become, respectively. In this state, after charging and discharging with 2C current for 15 hours continuously for 15 hours, charging and discharging with constant power were immediately performed, and the time until the battery voltage reached 3 V was determined. The power / time characteristics thus obtained were interpolated to obtain an output value in 3 seconds.

Further, the internal resistance was obtained by calculating the IV resistance value by the DCIR method in the above-described posture A, posture B, and posture C. Specifically, after each cell 100 placed in postures A, B, and C was left at 25 ° C. for 24 hours, it was charged with a constant current for 6 minutes until the battery voltage reached 4.1V. Thereafter, the battery was discharged at a current value (design value) of 2 C until the battery voltage reached 3 V in a thermostatic chamber at a temperature of 25 ° C., and the discharge capacity at this time was measured. Next, charging and discharging with 2C current based on the above-described actual measurement of the discharge capacity was continuously performed 30 times over 15 hours, and then immediately charged with a current value of 2C to a battery voltage of 4.1V. Immediately thereafter, discharging was performed at a maximum current value of 12 C, and the voltage drop after 10 seconds was measured. The relationship between the current value (X axis) and the voltage value (Y axis) at this time is expressed as an IV diagram, and the IV resistance value (internal resistance value) of each unit cell 100 is calculated based on this IV diagram. Calculated.
As a result, the size of the internal resistance and battery output in the single battery 100 arranged in the posture A was set to 1, and the internal resistance and the size of the battery output in the posture B and posture C were expressed as relative values with respect to the posture A. .

   The results of the survey are shown in Table 1.

According to Table 1, it can be seen that the unit cell 100 arranged in the posture B has a lower internal resistance and a larger battery output than the unit cells 100 in the posture A and the posture C.
This is because, as described above, by disposing the unit cell 100 in the posture B, the lower electrolyte solution LQ heated by the positive electrode plate terminal portion 111 that is relatively hot is directed upward, and conversely, Convection occurs where the electrolyte LQ located above moves downward, and heat moves inside the unit cell 100 (power generation element 110). Thereby, the difference in the temperature of each part in the electrode overlapping part 113 is suppressed, and the battery reaction occurring in the electrode overlapping part 113 occurs more uniformly than the unit cells 100 arranged in the posture A and the posture C. . For this reason, it is considered that the internal resistance in the unit cell 100 is further reduced, and the battery output is increased accordingly.
Thus, when the unit cell 100 is arranged such that the high temperature side terminal portion (positive electrode plate terminal portion 111) is vertically lower than its own low temperature side terminal portion (negative electrode plate terminal portion 112), it is charged or discharged. As a result, it was confirmed that the unit cell 100 had a lower internal resistance, a higher output, and better characteristics than those in the postures A and C.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. .
For example, in the embodiment, the single battery 100 constituting the assembled battery 10 is a lithium ion secondary battery. However, the type of the single battery is not limited to the present embodiment, and can be adopted for other types of batteries such as a nickel hydride secondary battery and a nickel cadmium secondary battery.

  In the embodiment, in the battery module 11 (11A, 11B) constituting the assembled battery 10, the unit cells 100 are connected in series. However, the connection method of the cells constituting the assembled battery may be connected in parallel, parallel series, or series-parallel. Further, the number of single cells constituting the assembled battery is not limited to this embodiment, and can be changed as appropriate.

  In the embodiment, the power generation element 110 includes a strip-shaped positive electrode plate 121, a negative electrode plate 122, and a separator 123, and is a wound type power generation element formed by winding the positive electrode plate 121 and the negative electrode plate 122 through the separator 123. It was. However, the power generation element may be a plate-stacked power generation element that includes a plurality of plate-like positive electrode plates, negative electrode plates, and separators, and alternately stacks positive electrode plates and negative electrode plates with separators interposed therebetween.

  In the embodiment, the vehicle 1 is a hybrid car. However, the type of vehicle may be a vehicle such as an electric vehicle, a forklift, an electric wheelchair, an electric assist bicycle, and an electric scooter.

1 is a perspective view showing a vehicle according to an embodiment. It is a perspective view which shows the battery pack mounted in the vehicle which concerns on embodiment. It is a figure which shows a part of assembled battery, and is an enlarged view of the principal part in FIG. It is a perspective view which shows the single battery which comprises the battery module of FIG. It is AA arrow sectional drawing of FIG. It is BB arrow sectional drawing of FIG. It is explanatory drawing for demonstrating each about the measuring method of temperature by a 1st investigation, and the attitude | position of a cell by a 2nd investigation. It is a figure which shows the result of a 1st investigation, and is a graph about the relationship between the cycle number of charging / discharging and the temperature change of an electric power generation element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Car body 10 Assembly battery 100 Single cell 110 Power generation element 111 Positive electrode plate terminal part (high temperature side terminal part)
112 Negative electrode terminal (low temperature side terminal)
113 Electrode Overlapping Section 121 Positive Electrode Plate 122 Negative Electrode Plate 123 Separator LQ Electrolyte

Claims (3)

An assembled battery that has a plurality of single cells and can be directly or indirectly attached to a vehicle body,
All of the above cells
A power generation element having a positive electrode plate, a negative electrode plate and a separator, and an electrolyte solution are provided inside,
The power generation element is
An electrode overlap portion in which the positive electrode plate and the negative electrode plate are overlapped via the separator;
Of the positive electrode plate, the negative electrode plate, and the separator, only the positive electrode plate extends from the electrode overlapping portion and is stacked,
A negative electrode plate terminal that is disposed on the opposite side of the positive electrode plate terminal portion via the electrode overlap portion, and of the positive electrode plate, the negative electrode plate, and the separator, only the negative electrode plate extends from the electrode overlap portion and overlaps. And
When the unit cell is arranged such that the negative plate terminal portion is at the same height in the vertical direction with respect to the positive plate terminal portion and charged or discharged, the positive plate terminal portion and the negative plate terminal portion Among them, when the relatively high temperature is the high temperature side terminal, and the low temperature is the low temperature side terminal,
In the state where the assembled battery is in a posture attached to the vehicle body,
Any of the plurality of unit cells
An assembled battery in which the high temperature side terminal portion is arranged in a posture that is vertically lower than the low temperature side terminal portion. The assembled battery according to claim 1,
The unit cell is
A lithium ion secondary battery using lithium oxide as a positive electrode active material carried by the positive electrode plate and carbon as a negative electrode active material carried by the negative electrode plate;
An assembled battery in which the high temperature side terminal portion is the positive electrode plate terminal portion. A vehicle on which the assembled battery according to claim 1 or 2 is mounted.

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