JP2021002487A - Battery module - Google Patents

Abstract

To provide a battery module that suppresses heat transfer to another battery cell when one battery cell overheats abnormally.SOLUTION: A battery module includes a plurality of battery cells, and a plate-shaped spacer placed between adjacent battery cells, and a gap is formed at least partially between at least one of the adjacent battery cells and the spacer, and the spacer has a thermal resistance of 6.55×10-6 or more per average calorific value when the battery cell is abnormal.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to battery modules.

A secondary battery is generally configured in the form of a battery unit comprising at least one battery module including a plurality of battery cells. Each battery cell generates heat when the secondary battery is charged and discharged. When the battery cell becomes hot, problems such as a decrease in battery capacity occur. Therefore, it is necessary to use the secondary battery while cooling each battery cell.

Patent Document 1 describes a technique for cooling a battery cell by flowing a cooling air between adjacent battery cells. In this technique, in order to eliminate the deviation between adjacent battery cells, a spacer having heat insulating properties is provided between the adjacent batteries.

On the other hand, in a battery module in which a plurality of battery cells are arranged, when one battery cell is short-circuited and abnormally heat is generated, the heat is transferred to another battery cell, and the battery cells in the battery module are short-circuited one after another and abnormally heat is generated. there's a possibility that. The forms of heat transfer in the battery module are heat conduction due to contact between battery cells, convection heat transfer (heat transfer) due to the contents (high temperature gas) ejected from the short-circuited battery cells, and radiation between the battery cells. You could think so.

Japanese Unexamined Patent Publication No. 2013-161720

On the other hand, the battery module of Patent Document 1 is merely provided with a spacer in order to eliminate the deviation between adjacent battery cells when cooling each battery cell during normal operation. When a certain battery cell in this battery module generates abnormal heat, the spacer can prevent the battery cells from coming into contact with each other, but it does not necessarily prevent heat conduction between the battery cells through the spacer.

In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a battery module that suppresses heat transfer to another battery cell when one battery cell abnormally generates heat.

The battery module according to at least one embodiment of the present disclosure includes a plurality of battery cells and a plate-shaped spacer arranged between adjacent battery cells, and is located between at least one of the adjacent battery cells and the spacer. A gap is formed at least partially, and the spacer has a thermal resistance of 6.55 × ^10-6 or more per average calorific value at the time of abnormality of the battery cell.

According to this configuration, even if a certain battery cell abnormally generates heat and swells, the spacer does not directly contact the adjacent battery cell, and the thermal resistance of the spacer per average heat generation amount at the time of abnormality of the battery cell is 6.55 × 10. ^When it is ⁻⁶ or more, heat conduction through the spacer is also suppressed, so that it is possible to suppress heat transfer to another battery cell when an abnormal heat generation occurs in one battery cell.

In some embodiments, a module case accommodating a plurality of battery cells may be provided, and the module case may include a fixing member for fixing a spacer between adjacent battery cells. In this case, the fixing member is an accommodating groove provided on the floor surface of the module case on which a plurality of battery cells are placed, and the accommodating groove may be configured so that a spacer can be inserted. Further, the fixing member may be a pair of elastically deformable claws fixed to the module case, and the pair of claws may be configured such that a spacer can be inserted between them. According to this configuration, spacers can be fixed between adjacent battery cells without deteriorating the cooling performance of the battery cells.

In some embodiments, the spacer comprises a pair of opposite edges, even if both surfaces of the spacer in contact with each of the adjacent battery cells are formed with flow path grooves extending between the pair of edges. Good. According to this configuration, a distribution flow path through which the cooling fluid for cooling the battery cells flows can be reliably formed between the adjacent battery cells.

According to at least one embodiment of the present disclosure, even if a battery cell abnormally generates heat and swells, the spacer does not directly contact the adjacent battery cell, and the heat of the spacer per average heat generation amount at the time of abnormality of the battery cell. When the resistance is 6.55 × ^10-6 or more, heat conduction through the spacer is also suppressed, so that when one battery cell overheats, heat transfer to another battery cell can be suppressed. it can.

It is a schematic diagram which shows the structure of a part of the battery module which concerns on Embodiment 1 of this disclosure. It is a schematic diagram which shows the structure when a certain battery cell in the battery module which concerns on Embodiment 1 of this disclosure abnormally generates heat and swells. It is a schematic diagram which shows the structure of a part of the modification of the battery module which concerns on Embodiment 1 of this disclosure. It is a schematic diagram which shows the structure of the battery module which concerns on Embodiment 2 of this disclosure. It is a figure which shows the structure of the fixing member of the battery module which concerns on Embodiment 3 of this disclosure. It is a perspective view of the spacer of the battery module which concerns on Embodiment 4 of this disclosure. It is a schematic diagram which shows the structure of a part of the battery module which concerns on Embodiment 4 of this disclosure. It is a schematic diagram which shows the structure of a part of the modification of the battery module which concerns on Embodiment 4 of this disclosure. It is a schematic diagram which shows the structure of a part of another modification of the battery module which concerns on Embodiment 4 of this disclosure.

Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, numbers, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention to that alone, but are merely explanatory examples.

(Embodiment 1)
As shown in FIG. 1, the battery module 1 according to the first embodiment of the present disclosure includes a plurality of battery cells 2, and a plate-shaped spacer 3 is provided between the adjacent battery cells 2 and 2. .. The spacer 3 is arranged so as to form a gap 4 between the adjacent battery cells 2 and 2 and the respective surfaces 2a and 2a facing each other. The spacer 3 has the same area as the area of the surface 2a. Although two battery cells 2 are shown in FIG. 1, the battery module 1 may include three or more battery cells 2.

When a cooling fluid such as cold air is circulated through each gap 4 during charging / discharging of the battery module 1, the cooling fluid comes into contact with each surface 2a, so that each battery cell 2 is cooled. As shown in FIG. 2, even if a certain battery cell 2'is abnormally generated by heat generation due to a short circuit or the like and swells, the spacer 3 does not directly contact the adjacent battery cell 2, so that the surface 2a'to the surface 2a Heat conduction can be prevented.

However, even if the spacer 3 prevents the adjacent battery cells 2 from coming into contact with each other, if the spacer 3 has a high thermal conductivity, the heat conduction from the abnormal battery cell 2'to the adjacent battery cell 2 cannot be suppressed. Therefore, the effect of suppressing the abnormality of one battery cell 2'spreading to another battery cell 2 cannot be obtained. Therefore, the spacer 3 is preferably formed of a heat insulating material.

The spacer 3 formed of the heat insulating material preferably has the characteristics described below. It is assumed that the energy generated when an abnormality occurs in the battery cell 2'is 40 [A · h] x 4.1 [V] = 164 [W · h] = 590 [kJ]. Assuming that it takes 207 [sec] to reach the maximum temperature in the battery cell 2'where the abnormality has occurred, the average calorific value of the battery cell until reaching the maximum temperature is 590 [kJ] ÷ 207 [sec] = It becomes 2850 [W]. Further, assuming that the thermal conductivity of the heat insulating material used is 0.02 [W / mK] and the thickness is 3 [mm], the thermal resistance of the heat insulating material is 0.02 [W / mK] × 3 [mm]. = 6.0 × ^10-5 [W / K]. Assuming that the average temperature difference between the battery cell 2'and the adjacent battery cell 2 until it reaches the maximum temperature is 311 [K], the heat of the heat insulating material per average calorific value from the battery cell 2'where the abnormality has occurred. The resistance is at least 6.0 × ^10-5 [W / K] ÷ (2850 [W] ÷ 311 [K]) = 6.55 × ^10-6 . Therefore, it is preferable that the spacer 3 has a thermal resistance of 6.55 × ^10-6 or more per average calorific value when the battery cell 2 ′ is abnormal.

The spacer 3 satisfying this condition can be produced from, for example, a heat insulating material having a thermal conductivity of 0.1 W / mK or less and a thickness of 5 mm. As such a heat insulating material, for example, a heat insulating sheet using hollow ceramic particles can be used. Specifically, Porextherm WDS (registered trademark) commercially available from Krosaki Harima Co., Ltd. can be used.

In this way, even if a certain battery cell 2'is abnormally generated and swells, the spacer 3 does not directly contact the adjacent battery cell 2, and the thermal resistance of the spacer per average heat generation amount at the time of abnormality of the battery cell 2'is increased. When the size is 6.55 × ^10-6 or more, heat conduction through the spacer 3 is also suppressed, so that when a certain battery cell 2'heats abnormally, heat transfer to another battery cell 2 is suppressed. be able to.

In the first embodiment, as shown in FIG. 1, a spacer 3 is provided so as to form a gap 4 between each battery cell 2 and each surface 2a, but the present invention is not limited to this embodiment. As shown in FIG. 3, the spacer 3 may be provided so as to be in contact with the surface 2a of one battery cell 2, and the gap 4 may be formed only between the surface 2a of the other battery cell 2.

(Embodiment 2)
Next, the battery module according to the second embodiment will be described. The battery module according to the second embodiment is obtained by adding a fixing member for fixing the spacer 3 between the adjacent battery cells 2 and 2 to the first embodiment. In the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the battery module 1 according to the second embodiment of the present disclosure is between the four battery cells 2, the module case 10 accommodating the four battery cells 2, and the adjacent battery cells 2 and 2. It is provided with a spacer 3 provided. However, 4 which is the number of battery cells 2 is merely an example, and the battery module 1 may include any number of battery cells 2 of 2, 3, or 5 or more.

A storage groove 12 is formed on the floor surface 11 on which each battery cell 2 is placed in the module case 10 so as to extend between the adjacent battery cells 2 and 2. The accommodating groove 12 is configured so that the vicinity of the lower end edge of the spacer 3 can be inserted. By accommodating the spacer 3 in the accommodating groove 12, the spacer 3 can be fixed between the adjacent battery cells 2 and 2. Therefore, the accommodating groove 12 constitutes a fixing member for fixing the spacer 3 between the adjacent battery cells 2 and 2.

The operation of cooling the battery cell 2 by flowing the cooling fluid through the gap 4 formed between the battery cell 2 and the spacer 3 during charging / discharging of the battery module 1 is the same as that of the first embodiment. Further, the principle that the spacer 3 suppresses heat conduction to another battery cell 2 when a certain battery cell 2 abnormally generates heat due to a short circuit or the like and swells is the same as that of the first embodiment. In the second embodiment, the accommodating groove 12 for fixing the spacer 3 is provided, but since the accommodating groove 12 is configured so that only the vicinity of the lower end edge of the spacer 3 is inserted, the accommodating groove 12 is provided. The reduction in the size of the gap 4 due to the provision can be suppressed as much as possible. Therefore, the spacer 3 can be fixed between the adjacent battery cells 2 and 2 without deteriorating the cooling performance of the battery cells 2.

(Embodiment 3)
Next, the battery module according to the third embodiment will be described. The battery module according to the third embodiment is a modification of the second embodiment in which the structure of the fixing member is changed. In the third embodiment, the same components as those of the second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, a pair of elastically deformable claws 15 and 15 are fixed to the module case 10. By inserting the spacer 3 between the claws 15 and 15, the spacer 3 can be fixed between the adjacent battery cells 2 and 2. Therefore, the pair of claws 15 and 15 form a fixing member for fixing the spacer 3 between the adjacent battery cells 2 and 2. In FIG. 5, the pair of claw portions 15 and 15 are drawn so as to sandwich the vicinity of the upper end edge of the spacer 3, but the pair of claw portions 15 and 15 may sandwich any portion of the spacer 3. Further, the pair of claw portions 15, 15 is not limited to one set, and two or more sets may be provided. Other configurations are the same as those in the first embodiment.

Also in the third embodiment, since the size reduction of the gap 4 can be suppressed as much as possible by providing the pair of claw portions 15 and 15, the adjacent battery cells 2 and 2 can be suppressed without deteriorating the cooling performance of the battery cells 2. The spacer 3 can be fixed between them.

(Embodiment 4)
Next, the battery module according to the fourth embodiment will be described. In the battery module according to the fourth embodiment, the configuration of the spacer 3 is changed for each of the first to third embodiments. In the following, the fourth embodiment will be described in which the configuration of the spacer 3 is changed from the configuration of the first embodiment. It may be configured. In the fourth embodiment, the same reference numerals as those of the constituent requirements of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the spacer 3 includes a pair of edges 3a, 3a facing each other. Channel grooves 20 extending between the pair of edge portions 3a and 3a are formed on both sides of the spacer 3, respectively.

As shown in FIG. 7, in the battery module 1 according to the fourth embodiment of the present disclosure, both surfaces of the spacer 3 other than the portion where the flow path groove 20 is formed between the adjacent battery cells 2 and 2 are each battery. The spacer 3 is provided so as to be in contact with each surface 2a of the cell 2. The space defined by the flow path groove 20 and the surface 2a constitutes the flow path 30 for the cooling fluid to flow. The distribution channel 30 has a rectangular cross-sectional shape. Other configurations are the same as those in the first embodiment. The distribution flow path 30 corresponds to the gap 4 (see FIG. 1) in the first embodiment.

In the fourth embodiment, the battery cell 2 is cooled by coming into contact with the surface 2a when the cooling fluid flows through the flow path 30. Although the contact area between the cooling fluid and the surface 2a is smaller than that of the first embodiment, by providing spacers 3 having the same configuration between the adjacent battery cells 2 and 2, the space between the adjacent battery cells 2 and 2 is provided. It is possible to eliminate each deviation of the above, and it is possible to cool each battery cell 2 evenly. The principle of suppressing heat transfer to another battery cell 2 when a certain battery cell 2 abnormally generates heat is the same as that of the first embodiment.

In FIG. 7, the cross-sectional shape of the distribution flow path 30 is rectangular, but the cross-sectional shape is not limited to this form. By adjusting the cross-sectional shape of the flow path groove 20, it is possible to form a distribution flow path 30 having a triangular cross-sectional shape as shown in FIG. 8, or a semicircular cross-sectional shape as shown in FIG. It is also possible to configure a distribution channel 30 having the above. Further, the cross-sectional shape of each distribution flow path 30 can be formed to be different from the others. That is, the cross-sectional shape of the flow path 30 can be arbitrary as long as the pressure loss when the cooling fluid flows is not significantly increased.

1 Battery module 2 Battery cell 2a (Battery cell) surface 3 Spacer 3a (Spacer) edge 4 Gap 10 Module case 11 Floor surface 12 Storage groove (fixing member)
15 Claw (fixing member)
20 Channel groove 30 Distribution channel

Claims (5)

With multiple battery cells
Equipped with a plate-shaped spacer placed between adjacent battery cells,
A gap is formed at least partially between at least one of the adjacent battery cells and the spacer.
The spacer is a battery module having a thermal resistance of 6.55 × ^10-6 or more per average calorific value when the battery cell is abnormal. A module case for accommodating the plurality of battery cells is provided.
The battery module according to claim 1, wherein the module case includes a fixing member for fixing the spacer between adjacent battery cells. The fixing member is a storage groove provided on the floor surface of the module case on which the plurality of battery cells are placed, and the storage groove is configured so that the spacer can be inserted. The battery module described. The fixing member is a pair of elastically deformable claws fixed to the module case, and the pair of claws is configured such that the spacer can be inserted between them. 2. The battery module according to 2. The spacer includes a pair of edges facing each other.
The battery module according to any one of claims 1 to 4, wherein flow path grooves extending between the pair of edges are formed on both surfaces of the spacers in contact with each of the adjacent battery cells.

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