JP2001060466A - Set battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently radiate the heat generated in a battery by connecting a cooling device capable of sending and discharging a coolant inside of a set battery case storing a plurality of cells. SOLUTION: Lithium ion secondary batteries 1 as a plurality of long cylindrical cells stored in a set battery case 4 manufactured by forming a stainless steel plate into the shape of a box, respectively have a positive electrode terminal 2 and a negative electrode terminal 3 projected from an upper end surface. The positive electrode terminal 2 is formed by an aluminum rod material, the negative electrode terminal 3 is formed by a copper rod material, and they are upwardly projected to the external through penetrated opening formed on the upper end surface of the set battery case 4, and the penetrated parts are sealed through a sealing material. The set battery case 4 has an inlet 4a at a lower part of one end and an outlet 4b at an upper part of the other end. An external cooling device circulates a coolant such as the insulating oil or the liquid paraffin in the set battery case 4 through the inlet 4a and the outlet 4b. The coolant flows among lithium ion secondary batteries 1 for cooling the same, whereby the positive electrode terminal 2 and the negative electrode terminal 3 are directly cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery such as a large-sized lithium ion secondary battery which generates a large amount of heat.

[0002]

2. Description of the Related Art The temperature of a battery rises due to a chemical reaction occurring at the electrodes during charging / discharging or heat generated by electric resistance at a positive / negative terminal through which a charging / discharging current flows. If the temperature rise is too large, the life of the battery may be shortened or the battery may be damaged. In particular, in the case of lithium ion batteries, the organic solvent is used for the electrolyte and carbon is also used for the negative electrode active material. is there.

[0003] Conventionally, in the case where a large number of large-capacity batteries having a large amount of heat are used as a battery pack, a gap is provided between the cells, and a natural ventilation or a cooling fan is used here. By forcibly ventilating and circulating air, a rise in battery temperature was suppressed.

[0004]

However, recently,
Batteries have also been used for powering electric vehicles and ships, and the size and capacity of these batteries have increased. In this case, the heat radiation efficiency may be insufficient. In addition, when a plurality of such cells are housed in an assembled battery case and used as an assembled battery, the heat radiation efficiency is further deteriorated.

[0005] For this reason, conventionally, with the increase in the size and the capacity of the assembled battery, there has been a problem that the temperature rise of the battery cannot be sufficiently suppressed.

SUMMARY OF THE INVENTION The present invention has been made in order to cope with such a situation, and has a cooling device capable of efficiently suppressing a rise in temperature by cooling a unit cell through a refrigerant in an assembled battery case. The purpose of the present invention is to provide an assembled battery.

[0007]

According to a first aspect of the present invention, there is provided an assembled battery in which a plurality of cells are housed in an assembled battery case, and terminals drawn from each of the cells are projected outside the assembled battery case. A cooling device for feeding and discharging the refrigerant into and from the battery pack case is connected.

[0008] According to the first aspect of the present invention, since the refrigerant sent from the cooling device flows through the inside of the battery pack case, each unit cell accommodated in the battery pack case can be efficiently cooled. Further, at this time, since the refrigerant directly contacts the terminals of each assembled battery and is cooled, heat can be efficiently radiated also from those terminals that generate a large amount of heat due to the charge / discharge current. In addition, since cooling can be performed using a refrigerant having a high thermal conductivity, heat radiation efficiency is improved as compared with air cooling.
Further, since there is no need to separately attach a structure for cooling to the outside of the battery pack case, operations such as installation of batteries and replacement of each battery pack become easy.

According to a second aspect of the present invention, the cooling device feeds a refrigerant from an inlet provided at a lower end of one end of the assembled battery case, and an outlet provided at an upper end of the other end of the assembled battery case. It is characterized in that the refrigerant is discharged from

According to the second aspect of the present invention, the low-temperature refrigerant is sent from the cooling device to the lower end portion inside the battery pack case, and moves upward when the temperature rises due to heat absorption there. The high-temperature refrigerant that has moved upward is discharged from the upper end inside the battery pack case. Therefore, the refrigerant can move efficiently within the battery case and cool efficiently.

According to a third aspect of the present invention, there is provided an assembled battery, wherein a plurality of the assembled battery cases are provided, and an outlet provided at an upper end portion of one adjacent assembled battery case and a note provided at a lower end portion of the other assembled battery case. The cooling device is connected to the inlet via a communication pipe, and the cooling device sends the refrigerant through an inlet provided at the lower end of the first assembled battery case, and the refrigerant flows through the outlet provided at the upper end of the last assembled battery case. Is discharged.

According to the third aspect of the present invention, even when a plurality of battery cases are installed, the cooling medium can be efficiently moved by sequentially moving the coolant inside the battery cases.

According to a fourth aspect of the present invention, there is provided the battery pack, wherein a spacer is disposed between the plurality of cells contained in the battery pack case.

According to the fourth aspect of the present invention, since a gap is reliably formed between the unit cells by the spacer, it is possible to prevent a sufficient flow of the refrigerant between these cells and a decrease in heat radiation efficiency. .

[0015]

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

1 to 3 show an embodiment of the present invention. FIG. 1 is a perspective view in vertical section for explaining the structure of an assembled battery case for accommodating a lithium ion secondary battery. FIG. 3 is a longitudinal sectional front view for explaining the structure of an assembled battery case for accommodating a lithium ion secondary battery, and FIG. 3 is a longitudinal sectional front view for explaining a connection state when a plurality of assembled batteries are installed.

In this embodiment, a case will be described in which three large-sized and large-capacity lithium ion secondary batteries are housed in a battery pack case. As shown in FIGS. 1 and 2, the lithium ion secondary battery 1 uses a long cylindrical unit cell. In each lithium ion secondary battery 1, a positive electrode terminal 2 and a negative electrode terminal 3 protrude from the upper end surface. The positive electrode terminal 2 is made of an aluminum bar, and the negative electrode terminal 3 is made of a copper bar. The positive electrode terminal 2 and the negative electrode terminal 3 each have a male screw formed on the outer periphery and a female screw hole opened on the upper end surface on the inner circumferential side.

The lithium ion secondary batteries 1 are housed three by three in the battery pack case 4. Battery pack case 4
Is a stainless steel plate formed in a box shape. In the battery pack case 4, an injection port 4a is formed at the lower end of one end so as to protrude to the outside and has a tubular inner hole penetrating therethrough. And a discharge port 4b through which the tubular inner hole penetrates is formed. Further, the positive electrode terminal 2 and the negative electrode terminal 3 protruding from each lithium ion secondary battery 1 protrude upward through a through hole formed in the upper end surface of the battery pack case 4.
However, since a nut is screwed to the positive electrode terminal 2 and the negative electrode terminal 3 via a sealing material or the like,
The inside is closed except for the inlet 4a and the outlet 4b.

As shown in FIG. 2, a spacer 5 can be interposed between the lithium ion secondary batteries 1 housed in the battery pack case 4. The spacer 5 may have any shape as long as a gap is reliably formed between the lithium ion secondary batteries 1 and may be fixed to the bottom surface of the battery pack case 4 or the like. However, it is preferable that the shape is not so large so that a wide space can be secured between the lithium ion secondary batteries 1 as much as possible.
Also, in the lithium ion secondary battery 1, it is usually better to prevent the battery cases from being electrically connected to each other.
This spacer 5 is also formed of an insulator.

In the battery pack case 4 having the above structure, a cooling device (not shown) is connected to the inlet 4a at the lower end and the outlet 4b at the upper end. The cooling device is a device that sends refrigerant into the battery pack case 4 from the inlet 4a, and radiates and circulates the refrigerant discharged from the outlet 4b again. As the refrigerant, insulating oil, liquid paraffin, or the like is used so as not to corrode the aluminum positive electrode terminal 2 or the copper negative electrode terminal 3 penetrating the cooling unit. This refrigerant may be directly radiated by a radiator or the like of the cooling device, or may be separately cooled at a temperature equal to or lower than the outside temperature by another refrigerant or the like.

When a plurality of assembled battery cases 4 having the above construction are installed, for example, as shown in FIG. 3, the discharge port 4b of one adjacent assembled battery case 4 and the other The inlet 4a is connected via the communication pipe 6.
Then, a cooling device (not shown) may be connected to the inlet 4a of the first assembled battery case 4 and the outlet 4b of the last assembled battery case 4, so that the refrigerant flows through each assembled battery case 4 in order.

According to the battery having the above structure, the refrigerant sent from the cooling device flows through the inside of the battery pack case 4.
Each lithium ion secondary battery 1 can be efficiently cooled. In addition, the low-temperature refrigerant is sent from the lower end portion inside the battery pack case, absorbs heat there, rises and is discharged from the upper end portion, so that the refrigerant can cool the inside of the battery case without waste. In addition, since a gap can be reliably formed between the lithium ion secondary batteries 1 by disposing the spacer 5, the refrigerant can be efficiently cooled through the gap. further,
If the inside of the battery pack case 4 is always filled with this refrigerant, the battery pack case 4 can be broken even in an environment where a large pressure is applied to the battery pack case 4 such as in the sea. It does not occur. In this case, the pressure is evenly applied to each of the lithium ion secondary batteries 1, but if necessary, a pressure equalizer may be attached to each of the lithium ion secondary batteries 1.

The above refrigerant can also directly cool the positive terminal 2 and the negative terminal 3. Since the positive electrode terminal 2 and the negative electrode terminal 3 of the large-sized large-capacity lithium ion secondary battery 1 supply a large discharge current, heat generation due to electric resistance also increases, particularly heat generation at the positive electrode terminal 2 using aluminum having high electric resistance. Is a major factor in battery temperature rise.
Therefore, if such a positive electrode terminal 2 and a negative electrode terminal 3 are directly cooled by a refrigerant, the temperature rise of the lithium ion secondary battery 1 can be effectively suppressed. Moreover, these positive electrode terminal 2 and negative electrode terminal 3 are made of a metal having high thermal conductivity,
Since the cross-sectional area is large to allow a large current to flow, the heat generated inside the lithium ion secondary battery 1 can also be efficiently radiated.

For cooling the positive electrode terminal 2 and the negative electrode terminal 3,
Since a refrigerant having a higher thermal conductivity than air is used, the heat radiation efficiency is further improved. Further, since the assembled battery case 4 itself has a structure for cooling, compared to a case where a structure for cooling is separately provided outside the assembled battery case 4, the installation of the battery and the assembled battery case unit are performed. Replacement work becomes easy.

In the above embodiment, insulating oil, liquid paraffin, or the like is used as the refrigerant, but water or other aqueous solutions, volatile organic solvents, or the like can be used as long as there is no risk of corrosion. In the above-described embodiment, the cooling device that circulates the refrigerant has been described. However, for example, in an environment where the cooling water can be sufficiently supplied from the outside, the cooling water may be simply taken in and discharged.

Further, in the above embodiment, the lithium ion secondary battery 1 has been described, but the present invention is not limited to the secondary battery. In addition, the present invention can be similarly applied to not only lithium ion batteries but also other non-aqueous electrolyte batteries using an organic solvent for the electrolyte, and the danger when the battery temperature rises is reduced. It is feasible.

[0027]

As is apparent from the above description, according to the battery pack of the present invention, the unit cells contained in the battery pack case can be efficiently radiated by the refrigerant, so that the heat generation of the battery is ensured. Can be suppressed.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a longitudinal sectional perspective view for explaining the structure of an assembled battery case for accommodating a lithium ion secondary battery.

FIG. 2 shows the first embodiment of the present invention, and is a longitudinal sectional front view for explaining the structure of an assembled battery case accommodating a lithium ion secondary battery.

FIG. 3, showing the first embodiment of the present invention, is a longitudinal sectional front view illustrating a connection state when a plurality of assembled batteries are installed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lithium ion secondary battery 2 Positive electrode terminal 3 Negative electrode terminal 4 Assembled battery case 4a Inlet 4b Outlet 5 Spacer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E322 AA06 AA09 AB01 DA03 FA01 5H011 AA02 BB01 CC06 DD11 DD21 EE01 FF04 GG01 HH01 5H020 AA04 AS11 CC06 CC18 CC22 CC29 CC43 DD01 DD18 EE01 HH03 MM34 5H031 AA09 CC08 EE01

Claims (4)

[Claims] 1. A plurality of cells are housed inside an assembled battery case, terminals drawn from each of the cells are projected outside the assembled battery case, and a refrigerant is sent and discharged into the assembled battery case. A battery pack comprising a cooling device connected thereto. 2. The cooling device according to claim 1, wherein the cooling device feeds a refrigerant from an inlet provided at a lower end of one end of the battery pack case and discharges the refrigerant from an outlet provided at an upper end of the other end of the battery pack case. The battery pack according to claim 1, wherein 3. A plurality of assembled battery cases are provided, and a communication pipe is formed between an outlet provided at an upper end of one adjacent assembled battery case and an inlet provided at a lower end of the other assembled battery case. And the cooling device sends the refrigerant through an inlet provided at the lower end of the first assembled battery case and discharges the refrigerant through an outlet provided at the upper end of the last assembled battery case. The battery pack according to claim 1, wherein: 4. The battery pack according to claim 1, wherein a spacer is disposed between the plurality of cells contained in the battery pack case.