JP2013037861A - Secondary battery device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery device capable of preventing reduction of a battery capacity as a battery pack by decreasing a voltage difference between batteries creating temperature gradient.SOLUTION: The secondary battery device in which a first battery cell row, a second battery cell row, and a third battery cell row are arranged in parallel so that the second battery cell row and the third battery cell row sandwich the first battery cell row includes: a first bus bar which connects respective battery cells consisting of the first battery cell row in series; a second bus bar which connects respective battery cells consisting of the second battery cell row in series; and a third bus bar which connects respective battery cells consisting of the third battery cell row and has a resistance value higher than that of the first bus bar.

Description

  Embodiments described herein relate generally to a secondary battery device and a manufacturing method thereof.

  Secondary batteries are used as power sources for a wide variety of applications. The main use was as a power source for small electric devices such as mobile phones, personal computers, and portable music players, but large batteries used in devices that require relatively large amounts of power, such as electric vehicles and power storage power sources. Development of equipment is recommended.

  In order to cope with an increase in the size of the battery, there is a method of manufacturing a secondary battery device (battery pack) in which a plurality of batteries are connected in multiple series and in parallel and used as a large-scale power source.

JP 10-188942 A

  Each battery cell constituting a secondary battery device (battery pack) that repeatedly charges and discharges generally generates heat during charging and discharging. For this reason, the temperature of the battery cell becomes higher than the environment in which it is used, and in the secondary battery device in which a plurality of battery cells are connected in series and parallel, the battery cell on the outer peripheral side close to the outside air and other battery cells are surrounded. In such a battery near the center, a temperature difference occurs during use.

  In addition, depending on the layout of the secondary battery device in the device, a temperature difference may be generated in each cell in the secondary battery device due to an external influence such as a cell near the heat source and other cells.

  Thus, when a temperature difference arises in a secondary battery apparatus, a battery cell with a low temperature will not have sufficient capacity compared with a battery cell with a high temperature. And when charging / discharging is controlled by the voltage of each battery cell which comprises a secondary battery apparatus, since charging / discharging is controlled by a battery with a small capacity | capacitance, the capacity | capacitance of the whole secondary battery apparatus will become small. .

  The secondary battery device according to the present embodiment aims to reduce a voltage difference between batteries in which a temperature difference occurs, and to suppress a decrease in capacity as a battery pack.

  The secondary battery device according to the present embodiment includes a first battery cell row, a second battery cell row, and a third battery cell row, the second battery cell row and the third battery cell. A secondary battery device in which the rows are installed in parallel across the first battery cell row, the first bus bar connecting the battery cells constituting the first battery cell row in series, and the second The second bus bar that connects the battery cells that constitute the battery cell row in series and the battery cells that constitute the third battery cell row are connected in series, and the resistance value is higher than that of the first bus bar. A high third bus bar.

The perspective view which shows an example of the external appearance of the secondary battery apparatus 10 which concerns on 1st Embodiment. The perspective view which shows an example of the external appearance of the battery cell 12 which concerns on 1st Embodiment. The figure which shows an example of the discharge time characteristic of the output voltage with respect to the temperature of the battery cell 12 which concerns on 1st Embodiment. The figure which shows an example of the discharge time characteristic of the output voltage with respect to the output current of the battery cell 12 which concerns on 1st Embodiment. The figure which looked at the secondary battery device 10 concerning a 1st embodiment from the upper surface. 1 is a circuit diagram of a secondary battery device 10 according to a first embodiment. The perspective view which shows an example of the external appearance of the secondary battery apparatus 10 which concerns on 2nd Embodiment. The figure which looked at the rechargeable battery device 10 concerning a 2nd embodiment from the upper surface. The circuit diagram of the secondary battery apparatus 10 which concerns on 2nd Embodiment. The figure which looked at the rechargeable battery device 10 concerning a 3rd embodiment from the upper surface. The circuit diagram of the secondary battery apparatus 10 which concerns on 3rd Embodiment. The top view which shows the modification of the secondary battery apparatus 10 concerning 3rd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view illustrating an appearance of a secondary battery device 10 according to the present embodiment.

  As shown in FIG. 1, the secondary battery device 10 has, for example, a configuration having a plurality of secondary battery cells 12 a,. These nine battery cells 12 are arranged in series by three battery cells and electrically connected by the bus bar 14 to form three battery cell rows. These three battery cell rows are arranged in parallel and electrically connected using the bus bar 14 to constitute the secondary battery device 10.

  FIG. 2 is a perspective view showing the appearance of the secondary battery cell 12.

  Each battery cell 12 (12a,... 12s) is a non-aqueous electrolyte secondary battery such as a lithium ion battery, for example, a flat, substantially rectangular parallelepiped outer container 21 made of aluminum or an aluminum alloy, and an outer container The electrode body accommodated together with the non-aqueous electrolyte, the positive electrode terminal 22a, and the negative electrode terminal 22b are provided.

  The outer container 21 has a container main body with an open upper end and a rectangular plate-shaped lid body that is welded to the container main body and closes the opening of the container main body, and is formed fluid-tight. The electrode body is formed in a flat rectangular shape, for example, by winding a positive electrode plate and a negative electrode plate in a spiral shape with a separator interposed therebetween, and further compressing in a radial direction.

  The positive electrode (positive electrode terminal) 22 a and the negative electrode (negative electrode terminal) 22 b are provided at both ends in the longitudinal direction of the lid body 23, and project from the lid body 23. The positive electrode terminal 22a and the negative electrode terminal 22b are connected to the positive electrode and the negative electrode of the electrode body, respectively. One terminal, for example, the positive electrode terminal 22 a is electrically connected to the lid body 23 and has the same potential as the outer container 21. The negative terminal 22 b extends through the lid body 23. Between the negative electrode terminal 22b and the lid 23, a sealing material made of an insulating material such as synthetic resin or glass, for example, a gasket is provided.

  An insulating film is wound around the container body except for the upper end and the lower end of the container. This film regulates expansion of the outer container and prevents a short circuit between the outer container and the other battery cell 12 or a short circuit between the outer container and the other member.

  As shown in FIG. 1, the bus bar 14 (14 a,..., 14 t) is a conductive member that electrically connects a plurality of battery cells 12 in series or in parallel. The plurality of battery cells 12 are arranged in the direction in which the positive electrode terminals and the negative electrode terminals of adjacent battery cells 12 are aligned. Each bus bar 14 is formed of a metal plate made of a conductive material, for example, aluminum. One end of the bus bar 14 is joined to the positive terminal 22a of the battery cell 12, and the other end is welded to the negative terminal 22b of the adjacent battery cell 12 to electrically connect these electrode terminals. Thus, the nine battery cells 12 are connected in series by the plurality of bus bars 14. Similarly, the plurality of battery cells 12 are also used when connected in parallel.

  FIG. 3 is a diagram illustrating an example of the discharge time characteristic of the output voltage with respect to the temperature of the battery cell 12. It shows that the output voltage decreases in a shorter time as the temperature of the battery cell 12 is lower. For example, when a battery cell 12 with a temperature of 10 ° C. and a battery cell 12 with a temperature of 35 ° C. are arranged in parallel and electrically connected, the discharge characteristics of one battery cell 12 with a temperature of 10 ° C. are low, so Compared with the battery cell 12, the output voltage exceeding a predetermined value can be maintained only for a short time.

  Therefore, the output time of the two batteries connected in parallel at a voltage higher than a certain voltage is shorter than that in the case where the two batteries are connected in parallel at 35 ° C.

  FIG. 4 is a diagram illustrating an example of the discharge time characteristic of the output voltage with respect to the output current of the battery cell 12. It shows that the more the current that is discharged, the shorter the output voltage.

  Here, 1C refers to a current value equal to the current capacity of the battery. In the case of a 20 [Ahr] battery, 1C means 20A, and 2C means 40A.

  For example, when a battery cell 12 that emits 5C and a battery cell 12 that emits 1C are arranged in parallel and electrically connected, the discharge characteristics of one battery cell 12 that emits 5C are low, and the other 1C Compared with the battery cell 12, the output voltage exceeding a predetermined value can be maintained only for a short time.

  Therefore, the battery cell output at 1C can be discharged for a longer time than the battery cell output at 5C.

  FIG. 5 is a view of the secondary battery device 10 according to the first embodiment as viewed from above.

  FIG. 6 describes FIG. 5 as a circuit diagram.

  As shown in FIGS. 5 and 6, the secondary battery device 10 of the present embodiment connects the negative electrode terminal of the battery cell 12a and the positive electrode terminal of the battery cell 12b in series using the bus bar 14b, and the negative electrode terminal of the battery cell 12b. And the positive terminal of the battery cell 12c are connected using a bus bar 14c to form a battery cell array (hereinafter referred to as an A column).

  Similarly, the negative terminal of the battery cell 12d and the positive terminal of the battery cell 12e are connected in series using the bus bar 14e, the negative terminal of the battery cell 12e and the positive terminal of the battery cell 12f are connected using the bus bar 14f, One row of battery cells is formed (hereinafter referred to as B row).

  Similarly, the negative electrode terminal of the battery cell 12g and the positive electrode terminal of the battery cell 12h are connected in series using the bus bar 14g, the negative electrode terminal of the battery cell 12h and the positive electrode terminal of the battery cell 12i are connected using the bus bar 14h, One row of battery cells is formed (hereinafter referred to as row C).

  These bus bars constituting each row can be collectively referred to as a bus bar group. In this case, it is good also as a bus-bar group including a part of bus-bar 14a, 14d corresponding to the electric current which flows into each row | line.

  These three battery cells A, B, and C are connected to the positive terminal of the battery cell 12a, the positive terminal of the battery cell 12d, and the positive terminal of the battery cell 12g by the bus bar 14a, and the negative terminal of the battery cell 12c and the battery The negative terminal of the cell 12f and the negative terminal of the battery cell 12i are connected by a bus bar 14d.

  The battery cells 12d, 12e, and 12f that are in a position where the battery cell 12 itself generates heat and does not easily dissipate heat when the current (electrical energy) is output in the battery cells arranged in three series and three in parallel. The battery cells 12a, 12b, 12c, 12g, 12h, and 12i are in a higher temperature state.

  Here, the bus bars 14b, 14c, 14g, and 14h of the present embodiment have higher resistance values than the bus bars 14e and 14f. In order to realize a high resistance value, there is a method of increasing the resistance with respect to the input current, for example, a method of narrowing a part of the area as shown in FIG.

  In the secondary battery device 10 configured as described above, the total resistance value in the A row and the total resistance value in the C row are higher than the total resistance value in the B row.

  That is, according to Ohm's law, when the output voltage output from the A column, the B column, and the C column is a constant value, the amount of current that flows or is transmitted from the A column and the C column flows or is transmitted from the B column. Less than the current amount.

  3 and FIG. 4 in consideration of this, the resistance values of the bus bars connecting the rows A and C are the same as the resistance values of the bus bars connecting the rows B and C in the low temperature state. The current can be sent at a certain voltage or higher over a longer time than in the case.

  Therefore, it is possible to realize a long current transmission time for the entire secondary battery device 10 having battery cells having a temperature difference.

  In this embodiment, 14b, 14c, 14g, and 14h are illustrated as if they have the same resistance value, but the resistance value can be changed according to each embodiment and temperature change. That is, the resistance value of each bus bar and bus bar group corresponds to the temperature state of the battery cells constituting the secondary battery device, reduces the output current of the battery cells in a low temperature state, and the battery cells in a high temperature state. For example, a value designed to output a high current value can be used.

  In the present embodiment, the description has been given using the three battery cell rows. However, instead of the C row, for example, a heat source such as an engine or a motor installed in the vehicle may be used. In this case, the row B near the heat source hardly releases heat and may absorb heat from the outside, and the temperature becomes higher than the row A. Applicable.

(Second Embodiment)
FIG. 7 is a perspective view showing an appearance of the secondary battery device 10 according to the second embodiment.

  As shown in FIG. 7, the secondary battery device 10 of the present embodiment has a configuration having a plurality of secondary battery cells 12 j,. These eight battery cells 12 are arranged in series and electrically connected by a bus bar 14 to form two battery cell rows. These two battery cell rows are arranged so as to have an electrically parallel structure, and are electrically connected using the bus bar 14 to constitute the secondary battery device 10. For the sake of simplicity, explanations are omitted with respect to what has been described using the same reference numerals as in the first embodiment.

  FIG. 8 is a top view of the secondary battery device 10 according to the second embodiment.

  FIG. 9 describes FIG. 8 as a circuit diagram.

  As shown in FIGS. 8 and 9, the secondary battery device 10 of the present embodiment connects the negative electrode terminal of the battery cell 12k and the positive electrode terminal of the battery cell 12j in series using the bus bar 14j, and the negative electrode terminal of the battery cell 12j. And the positive electrode terminal of the battery cell 12p are connected using the bus bar 14i, and the negative electrode terminal of the battery cell 12p and the positive electrode terminal of the battery cell 12q are connected using the bus bar 14p to constitute one battery cell row. (Hereinafter referred to as column D).

  Similarly, the negative electrode terminal of the battery cell 12m and the positive electrode terminal of the battery cell 12l are connected in series using the bus bar 14m, the negative electrode terminal of the battery cell 12l and the positive electrode terminal of the battery cell 12n are connected using the bus bar 14l, The negative electrode terminal of the battery cell 12n and the positive electrode terminal of the battery cell 12o are connected by using the bus bar 14n to constitute one battery cell array (hereinafter referred to as E column).

  These bus bars connecting the columns in series can be collectively referred to as a bus bar group. Moreover, it is good also as a bus-bar group including some bus-bars 14k and 14o through which the electric current of each row | line | column flows.

  Each battery cell row of D and E is connected to the positive terminal of the battery cell 12k and the positive terminal of the battery cell 12m with the bus bar 14k, and the negative terminal of the battery cell 12o and the negative terminal of the battery cell 12q with the bus bar 14o. Connected.

  Here, as shown in FIG. 7, the row D is installed so as to be surrounded by the row E.

  Therefore, in the battery cells arranged in 4 series and 2 parallel, when the current (electric energy) is output, the battery cells 12 l, 12 m, 12 n, 12 o are in positions where the battery cells 12 themselves generate heat and are not easily dissipated. The battery cells 12j, 12k, 12p, and 12q have a higher temperature than the surrounding battery cells 12j, 12k, 12p, and 12q.

  Here, the bus bar 14i of the present embodiment has a longer connection distance and a higher resistance value than the bus bar 14l.

  In the secondary battery device 10 configured as described above, the total resistance value in the D row is higher than the total resistance value in the E row.

  That is, according to Ohm's law, when the output voltage output from the D column and the E column is a constant value, the amount of current flowing from or transmitted to the D column is smaller than the amount of current flowing from or transmitted to the E column. .

  When this is applied to FIG. 3 and FIG. 4 described in the first embodiment, the resistance value of the bus bar connecting the D row is the resistance value of the bus bar connecting the D row in the D row in the low temperature state. As compared with the same case, a current of a certain voltage or more can be sent for a long time.

  Therefore, it is possible to realize a long current transmission time for the entire secondary battery device 10 having a secondary battery having a temperature difference.

  In this embodiment, 14j, 14l, 14m, 14n, and 14p are described as if they have the same resistance value, but the resistance value can be changed in accordance with each embodiment and temperature change. . That is, the resistance value of each bus bar and bus bar group corresponds to the temperature state of the battery cells constituting the secondary battery device, reduces the output current of the battery cells in a low temperature state, and the battery cells in a high temperature state. For example, a value designed to output a high current value can be used.

(Third embodiment)
The secondary battery device 10 of the present embodiment is configured to have a plurality of secondary battery cells 12r and 12s as shown in FIGS. The total two battery cells 12 are arranged so as to have an electrically parallel structure, and are electrically connected using the bus bar 14 to constitute the secondary battery device 10. For the sake of simplification, the description using the same reference numerals as those in the first or second embodiment is omitted.

  FIG. 10 is a top view of the secondary battery device 10 according to the third embodiment.

  FIG. 11 is a circuit diagram of FIG.

  The secondary battery device 10 of the present embodiment connects the positive terminal of the battery cell 12r and the positive terminal of the battery cell 12s in parallel using the bus bar 14q, and connects the negative terminal of the battery cell 12r and the negative terminal of the battery cell 12s, The bus bar 14r is used for connection.

  Here, it is assumed that the temperature of the cell 12r is higher than that of the cell 12s. For example, this is a case where there is a heat source on the cell 12r side. The heat source may be an automobile engine, or a heat generating part inside a television or a personal computer. Moreover, when using as a stationary type, the medium which produces the solar heat which arises with sunlight can also be used as a heat source. An example is a case where it is installed at a position closer to the sun than 12r and 12s.

  In this case, as shown in FIG. 10, the bus bars 14q and 14r of the present embodiment are configured such that the connection distance to 12s is longer and the resistance value is higher than the connection distance to the cell 12r.

  In the secondary battery device 10 configured as described above, the resistance value with respect to the current flowing through the cell 12s is higher than the resistance value with respect to the current flowing through the 12r.

  That is, according to Ohm's law, when the output voltage output from each battery cell 12r, 12s is a constant value, the amount of current flowing from or sent out from the cell 12s is greater than the amount of current flowing from or sent out from the cell 12r. Few.

  When this is applied to FIG. 3 and FIG. 4 described in the first embodiment, the cell 12s in the low temperature state takes a longer time than the case where the resistance value of the bus bar with respect to the cell 12r is configured to be the same. Thus, the current can be sent at a certain voltage or higher.

  Therefore, it is possible to realize a long current transmission time for the entire secondary battery device 10 having a secondary battery having a temperature difference.

(Modification)
As a third modified example, as shown in FIG. 12, the resistance value of the bus bars 14s and 14t may be increased with respect to a battery having a low temperature.

  In the bus bar 14 described in each embodiment, the bus bar area is reduced with respect to the direction perpendicular to (or twisted) the current flowing in the battery (this current direction is referred to as a virtual line) and parallel to the virtual line. By increasing the distance in the direction of, the resistance value of the bus bar can be increased. By performing the reverse shape change, the resistance value of the bus bar can be lowered.

  Further, for example, a lithium ion secondary battery that is a non-aqueous secondary battery constituting the secondary battery device described in each embodiment is a power source of an electric vehicle, a hybrid electric vehicle, an electric bicycle, or a power source of an electric device. Can be used as

  In addition, when applied to these, the secondary battery is a battery in which a plurality of battery cells are arranged in a case in order to increase the capacity and output, and these battery cells are connected in parallel or in series. A module can be configured, and a plurality of battery modules can be connected to form a battery pack for use.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. For example, although the upper surface cover and the connecting member are described as metal members in the present embodiment, so-called lamellar battery cells may be used. In each embodiment, the description is made using nine battery cells in the first embodiment, eight battery cells in the second embodiment, and two battery cells in the third embodiment. However, the number is limited to this number. There is no. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10 ... Secondary battery device 12 (12a, ... 12s) ... Battery cell (cell)
14 (14a, ..., 14t) ... bus bar 21 ... outer can 22a ... positive electrode (positive electrode terminal)
22b ... Negative electrode (negative electrode terminal)
23 ... Lid (lid)

Claims (8)

A first battery cell row having two battery cells connected in series;
A second battery cell row having two battery cells connected in series;
A third battery cell row having two battery cells connected in series;
With
The first battery cell row, the second battery cell row, and the third battery cell row are the first battery cell, and the second battery cell row and the third battery cell row are the first battery cells. A secondary battery device installed in parallel across a row,
A first bus bar for connecting each battery cell constituting the first battery cell row in series;
A second bus bar for connecting each battery cell constituting the second battery cell row in series;
Connecting each battery cell constituting the third battery cell row in series, a third bus bar having a resistance value higher than that of the first bus bar;
A secondary battery device comprising: The second bus bar is
2. The secondary battery device according to claim 1, wherein the resistance value is higher than that of the first bus bar. The first battery cell row includes:
It is configured by connecting multiple battery cells in series,
The second battery cell row includes:
It is configured by connecting multiple battery cells in a row,
The third battery cell row is:
It is configured by connecting a plurality of battery cells in series,
A first bus bar group connecting the battery cells constituting the first battery cell row in series;
A second bus bar configured by connecting each battery cell constituting the second battery cell row in series and having a resistance value that is higher than a total resistance value of the first bus bar group. Group,
A secondary battery device according to claim 1. A third bus bar configured by connecting each battery cell constituting the third battery cell row in series and having a resistance value having a total resistance value higher than a total resistance value of the first bus bar group. Group,
The secondary battery device according to claim 3, further comprising: The third bus bar is
The secondary battery device according to claim 1, wherein a connection distance is longer than that of the first bus bar. A fourth battery cell row having two battery cells connected in series;
A fifth battery cell row having two battery cells connected in series;
With
The battery cells constituting the first battery cell row and the second battery cell row are installed in parallel,
A fourth bus bar for connecting each battery cell constituting the fourth battery cell row in series;
A fifth bus bar for connecting the battery cells constituting the fifth battery cell row in series at a distance longer than that of the fourth bus bar;
A secondary battery device comprising: A first battery cell comprising a positive terminal and a negative terminal;
A second battery cell comprising a positive terminal and a negative terminal;
A sixth bus bar for connecting the positive terminal of the first battery cell and the positive terminal of the second battery cell to each battery cell with different resistance values;
A seventh bus bar for connecting the negative electrode terminal of the first battery cell and the negative electrode terminal of the second battery cell to each battery cell with different resistance values corresponding to the sixth bus bar;
A secondary battery device comprising: A first battery cell row having two battery cells connected in series;
A second battery cell row having two battery cells connected in series;
A third battery cell row having two battery cells connected in series;
With
The first battery cell row, the second battery cell row, and the third battery cell row, and the first battery cell row, the second battery cell row, and the third battery cell. A method of manufacturing a secondary battery device that is sandwiched between rows and installed in parallel,
Each battery cell constituting the first battery cell row is connected in series using a first bus bar,
Each battery cell constituting the second battery cell row is connected in series using a second bus bar,
A method for manufacturing a secondary battery device, wherein battery cells constituting the third battery cell array are connected in series using a third bus bar having a higher resistance value than the first bus bar.

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