JP2024046952A - Battery pack and method for manufacturing the battery pack - Google Patents

Abstract

[Problem] To provide a battery pack and a method for manufacturing the battery pack that can reduce manufacturing costs. [Solution] The spacers 150 of the battery pack 1 are provided with two sets of seal structures 170, each set consisting of a bar portion 161, a hollow portion 171, and a fin portion 174, for two adjacent spacers that are separated by a battery cell 100. The bar portion 161 is provided on one spacer 150 and extends toward the other spacer 150. The hollow portion 171 is provided on the other spacer 150, and the bar portion 161 provided on the one spacer 150 is press-fitted into the hollow portion 171. The fin portion 174 is provided on the lower surface 173 of the hollow portion 171, and a tip 176 is in contact with a bottom inner wall surface 203 of a case member 200. A cooling passage 300 is formed between the fin portions 174 of the two sets of seal structures 170 between the bottom inner wall surface 203 of the case member 200 and the battery stack 10. [Selected Figure] FIG. 4

Description

The disclosed technology relates to a battery pack having a battery stack in which battery cells are stacked and a case member that houses the battery stack, and a method for manufacturing the battery pack.

A battery pack is generally constructed by housing a battery stack, which is made by stacking multiple battery cells with spacers between them, in a case. An example of a spacer used in such a battery pack is described in Patent Document 1. In this document, the battery cells are stacked while being assembled into a battery holder that acts as a spacer to separate the battery cells. The battery holder is provided with passages through which cooling air passes to cool the battery cells. In the battery pack, the passages provided in the battery holder fit together and are connected to form a cooling passage through which cooling air passes in the stacking direction of the battery cells.

JP 2008-103248 A

Here, it is desirable for the battery pack to have as simple a structure as possible, because this allows the manufacturing costs of the battery pack to be reduced. However, in the conventional technology described above, there is a problem in that the shape of the battery holder becomes complicated because a passage for passing cooling air is provided in the battery holder.

The disclosed technology has been made to solve the problems of the conventional technology described above. In other words, the objective of the technology is to provide a battery pack and a method for manufacturing the battery pack that can reduce manufacturing costs.

One aspect of the disclosed technology is a battery pack having a battery stack in which multiple battery cells are stacked with spacers between them, and a case that houses the battery stack from one end side in the stacking direction of the battery cells, and a cooling passage that allows a fluid that cools the battery cells to pass in the stacking direction between the inner wall surface of the case and the battery stack, and the spacer has two sets of sealing structures for two adjacent spacers separated by a battery cell, each of which has a bar portion on one side that extends in the stacking direction toward the other side, a deformation portion on the other side that is deformed by the bar portion on the one side being pressed against the other side, and a fin portion on the deformation portion that has a tip that contacts the inner wall surface of the case, and the cooling passage is formed between the fin portions of the two sets of sealing structures between the inner wall surface of the case and the battery stack.

In the battery pack of the above embodiment, a cooling passage is provided between the fins of the two sets of sealing structures between the inner wall surface of the case and the battery stack. This allows the spacer structure to be simplified, thereby reducing the manufacturing cost of the battery pack.

In the battery pack of the above aspect, the case is further provided with a groove portion extending in the stacking direction at the cooling passage on the inner wall surface, the spacer has a fixed shape portion that fixes adjacent battery cells in the width direction of the groove portion, and it is preferable that the tips of the fin portions related to the two sets of seal structures are respectively in contact with different side surfaces of the two opposing side surfaces of the groove portion. In this way, the fin portions related to the two sets of seal structures are each subjected to a reaction force from the opposing different side surfaces of the groove portion. This reaction force allows the spacer and the battery cells fixed to the spacer to be appropriately aligned in the stacking direction. In other words, the configuration for forming the cooling passage can even align the battery cells in the battery stack. Therefore, there is no need to provide a special configuration for aligning the battery cells. This reduces the manufacturing cost of the battery pack.

In the battery pack of the above aspect, it is further preferable that the deformation portion is deformed so as to swing the fin portion by pressing the bar portion against the fin portion, compared to when the bar portion is not pressed against the fin portion. In this way, the fin portion that moves in a swinging manner can be deformed so as to bend overall, and can be brought into contact with the inner wall surface of the case. This makes it possible to properly form a cooling passage while preventing damage to the sealing structure and the case.

In the battery pack of the above aspect, it is further preferable that the deformation portion has a space extending in the stacking direction and is deformed by pressing the bar portion into the space. In this way, the deformation portion can be easily deformed by pressing the bar portion into the space, while deformation due to vibration or the like is unlikely to occur before the bar portion is pressed into the space.

In the battery pack of the above aspect, the case further has a floor portion located below the battery stack, an end panel attached to one end side in the stacking direction, and an end wall portion located on the other end side opposite the attachment point of the end panel and integral with the floor portion, and it is desirable that the battery stack is held in the case while being sandwiched between the end panel and the end wall portion. In this way, the battery stack and the end panel can be fixed by the compressive reaction force of the battery stack. In other words, for example, fastening or joining to fix the end panel is not necessary. This allows the manufacturing cost of the battery pack to be reduced.

Another aspect of the disclosed technology is a method for manufacturing a battery pack having a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween, and a case that houses the battery stack from one end side in the stacking direction of the battery cells, and a cooling passage is provided between the inner wall surface of the case and the battery stack to allow a fluid for cooling the battery cells to pass in the stacking direction, and the spacer is provided with a bar portion provided on one of two adjacent battery cells that extends in the stacking direction toward the other side, a deformation portion provided on the other side that deforms when the bar portion provided on the one side is pressed against the deformation portion, and a spacer provided on the deformation portion that has a tip that is in contact with the inside of the case when the bar portion is not pressed against the deformation portion and has a tip that is in contact with the inside of the case when the bar portion is not pressed against the deformation portion. In a pressed state in which the deformed portion is deformed by pressing the bar portion against the deformed portion without contacting the wall surface, a sealing structure having two sets of fin portions whose tips contact the inner wall surface of the case is used, and the battery stack is inserted into the case from one end side of the case by pressing the battery stack from one end side of the case with the bar portion not pressed against the deformed portion, and further, while applying a compressive load in the stacking direction to the battery stack, the bar portion is pressed against the deformed portion, and the bar portion is pressed against the deformed portion, so that the tips of the fin portions come into contact with the inner wall surface of the case, forming a cooling passage between the fin portions of the two sets of sealing structures between the inner wall surface of the case and the battery stack.

The manufacturing method of the battery pack in the above aspect can prevent the fin portion from coming into contact with the case when the battery stack is inserted into the case. In addition, when the battery stack is inserted into the case and accommodated, the fin portion can be brought into contact with the inner wall surface of the case to form a cooling passage. This makes it possible to provide a cooling passage between the fin portions of the two sets of sealing structures between the inner wall surface of the case and the battery stack, while preventing the fin portion and the case from being damaged by contact. A spacer with a simple structure is used to form the cooling passage. This allows high-quality battery packs to be manufactured at low cost.

In the manufacturing method of the battery pack of the above aspect, it is further preferable to use a case in which a groove portion extending in the stacking direction is provided at the cooling passage on the inner wall surface, and a spacer having a fixed shape portion that fixes adjacent battery cells in the width direction of the groove portion, and in a state in which the bar portion is pressed against the deformation portion, the tips of the fin portions related to the two sets of sealing structures are brought into contact with different sides of the two opposing side surfaces of the groove portion. In this way, the battery stack can be accommodated in the case, and the fin portions related to the two sets of sealing structures can be brought into contact with the opposing side surfaces of the different groove portions. Then, the reaction force can appropriately align the spacer and the battery cells fixed to the spacer in the stacking direction. In other words, the configuration for forming the cooling passage can align the battery cells in the battery stack. Therefore, there is no need to provide a special configuration for aligning the battery cells. This reduces the manufacturing cost of the battery pack.

In the manufacturing method of the battery pack of the above aspect, it is further preferable to use a spacer that displaces the fin portion so as to swing when the portion of the deformation portion where the fin portion is provided changes from a non-pressure-contact state to a pressure-contact state. In this way, the battery stack can be housed in the case, and the fin portion that moves so as to swing can be deformed so as to bend overall and contacted with the inner wall surface of the case. In addition, the amount of deformation of the deformation portion can be kept small while ensuring a large amount of movement of the tip of the fin portion. This makes it possible to suppress deformation of the hollow portion and suppress damage thereto, while ensuring sufficient clearance between the fin portion and the case when the battery stack is inserted into the case member. This makes it possible to properly form a cooling passage while preventing damage to the seal structure and case.

In the manufacturing method of the battery pack of the above aspect, it is further preferable to use a spacer in which the deformation portion has a space extending in the stacking direction and is deformed by pressing the bar portion into the space. In this way, the deformation portion can be easily deformed by pressing the bar portion, while deformation due to vibration or the like is unlikely to occur before the bar portion is pressed in. This makes it possible to more reliably prevent the fin portion from coming into contact with the case when inserting the battery stack into the case.

In the manufacturing method of the battery pack of the above aspect, further, a case having a floor portion located below the battery stack, an end panel attached to one end side in the stacking direction, and an end wall portion located on the other end side opposite the attachment point of the end panel and integrally connected to the floor portion is used, and the battery stack is pressed from one end side with the bar portion not pressed against the deformation portion, the other end side of the battery stack is pressed against the end wall portion to apply a compressive load in the stacking direction to the battery stack, while the bar portion is pressed against the deformation portion, the end panel is attached to the case, and the pressure on the battery stack from one end side is released to bring one end side in the stacking direction into contact with the end panel, so that the battery stack is sandwiched between the end wall portion and the end panel and held by the case. In this way, the battery stack and the end panel can be fixed by the compression reaction force of the battery stack. That is, for example, fastening or joining for fixing the end panel is not necessary. Therefore, the manufacturing cost of the battery pack can be reduced.

The disclosed technology provides a battery pack and a method for manufacturing the battery pack that can reduce manufacturing costs.

1 is an external perspective view of a battery pack according to an embodiment; FIG. 2 is an exploded perspective view of a battery cell and a spacer according to an embodiment of the present invention. FIG. 2 is a perspective view of a spacer according to an embodiment. 2 is a cross-sectional view in a width direction of the battery pack according to the embodiment. FIG. FIG. 4 is a diagram showing a state before a bar portion is press-fitted into a hollow portion of the spacer according to the embodiment. FIG. 2 is a diagram showing a state before the battery pack according to the embodiment is assembled; 4A and 4B are diagrams illustrating how the battery pack according to the embodiment is assembled.

Below, an embodiment of the disclosed technology will be described in detail with reference to the attached drawings.

In this embodiment, the disclosed technology is applied to a battery pack 1, the overall configuration of which is shown in FIG. 1. The battery pack 1 in FIG. 1 is configured by housing a battery stack 10 inside a battery case 20.

The battery stack 10 is composed of multiple rectangular battery cells 100. The multiple battery cells 100 in the battery stack 10 are stacked in the X direction shown in FIG. 1. The battery cells 100 shown in FIG. 1 are shown with their width direction aligned in the Y direction and their height direction aligned in the Z direction. The battery pack 1 of this embodiment has two battery stacks 10 arranged side by side in the Y direction. The X and Y directions are horizontal directions, and the Z direction is vertical. The multiple battery cells 100 in the battery stack 10 are stacked with spacers 150 interposed between them.

The battery case 20 has a bottom 22 located below the battery stack 10 and side walls 23 extending upward from the bottom 22, and is generally box-shaped with an open top. The battery case 20 has two storage spaces 21 formed by being surrounded by the bottom 22 and the side walls 23. The two battery stacks 10 are respectively housed in the two storage spaces 21.

The battery case 20 has a case member 200 and an end panel 250 assembled to the case member 200. The case member 200 has a floor portion 210 that constitutes the bottom portion 22. The case member 200 also has an end wall portion 220 that constitutes the side wall 23 at one end in the stacking direction of the battery cells 100. The floor portion 210 and the end wall portion 220 are part of the case member 200 and are connected to each other.

The case member 200 has an opening 225 at the end opposite the end wall portion 220 in the stacking direction of the battery cells 100. An attachment portion 226 is provided at the edge of the opening 225 of the case member 200. A plate-shaped end panel 250 is attached to the attachment portion 226 of the case member 200. The attachment portion 226 is a groove-shaped portion provided on the inside of the side wall 23 along the opening 225 of the case member 200. The end panel 250 is attached by being inserted from above into the attachment portion 226 of the case member 200. The opening 225 of the case member 200 is blocked by the end panel 250 attached to the attachment portion 226. Note that a cover member or the like that covers the upper portion of the battery pack 1 is appropriately attached depending on the actual usage situation, etc.

The battery stack 10 has end plates 180, 190 at both ends in the stacking direction of the battery cells 100. The end plate on the end panel 250 side is the first end plate 180, and the end plate on the end wall portion 220 side of the case member 200 is the second end plate 190.

The first end plate 180 in this embodiment is composed of a base plate 181 and a pressed plate 182. The pressed plate 182 is located closer to the end panel 250 than the base plate 181. The pressed plate 182 is provided with a pressed portion 183. The pressed portion 183 is a portion that receives pressure when the battery stack 10 is pressed in the stacking direction of the battery cells 100 during the manufacturing process of the battery pack 1.

The pressed plate 182 is held to the base plate 181 by a plate holding portion 184 provided on the base plate 181. In this embodiment, the plate holding portion 184 is a snap fit. The base plate 181 may be made of a material such as an insulating resin. The pressed plate 182 has a higher strength than the base plate 181. The pressed plate 182 may be made of a material such as a metal.

The end panel 250 of this embodiment also has an upper surface portion 251 at the top. The upper surface portion 251 is a portion that receives downward pressure when the end panel 250 is attached to the attachment portion 226. The end panel 250 has a recess 252. The recess 252 is provided at a position corresponding to the pressed portion 183 of the first end plate 180. The recess 252 has a notch shape formed from the lower end of the end panel 250 to the upper side. The recess 252 has a shape for attaching the end panel 250 to the attachment portion 226 while pressing the first end plate 180.

A cooling passage 300 is provided between the battery stack 10 and the battery case 20 in the battery pack 1. The cooling passage 300 is a space through which a fluid that cools the battery cells 100 passes in the stacking direction of the battery cells 100. In this embodiment, the cooling passage 300 is provided in the lower part of the battery pack 1.

Figure 2 is an exploded perspective view of a battery cell 100 and a spacer 150 to which the battery cell 100 is assembled. The battery cell 100 of this embodiment uses a conductive metal for the exterior. Two pole terminals 102 are provided on the top surface 101 of the battery cell 100. One of the two pole terminals 102 is a positive electrode and the other is a negative electrode.

Figure 2 shows a bus bar 30 for electrically connecting the pole terminals 102 of the multiple battery cells 100 to each other. As shown in Figure 1, the bus bar 30 in the battery pack 1 is connected to each of the battery cells 100. Therefore, in the battery pack 1, it is preferable that the positions of the pole terminals 102 of the multiple battery cells 100 are aligned. Specifically, it is preferable that the position in the width direction of the pole terminals 102 is constant for all of the multiple battery cells 100 in the battery pack 1. This is because the multiple pole terminals 102 are aligned in the stacking direction of the battery cells 100, making it possible to easily and appropriately connect the pole terminals 102 by the bus bar 30.

The spacer 150 is made of an insulating material. For example, an insulating resin can be used as the material of the spacer 150. The spacer 150 has a recess 151 on the side of the battery cell 100 to be assembled. In the battery stack 10, the battery cell 100 is fitted into the recess 151 of the spacer 150. In this way, the battery cell 100 and the spacer 150 are assembled and fixed to each other. In other words, the spacer 150 fixes the adjacent battery cells 100 in the width direction by the fixing surfaces 152 located at both ends of the width direction.

In the battery stack 10, multiple assemblies of battery cells 100 and spacers 150 are arranged in the X direction. As a result, in the battery stack 10, multiple battery cells 100 are stacked with the spacers 150 interposed between them. The spacers 150 insulate the battery cells 100 from each other in the battery stack 10.

In addition, two alignment protrusions 153 are provided below the spacer 150. The two alignment protrusions 153 are arranged with a gap between them in the width direction of the battery cell 100. Furthermore, two seal portions 160 are provided between the two alignment protrusions 153. The two seal portions 160 provided on the spacer 150 are symmetrical in shape with respect to the width direction of the battery cell 100.

The seal portion 160 has a bar portion 161 that extends in the stacking direction of the battery cells 100. In the battery stack 10, the bar portion 161 protrudes toward the adjacent other spacer 150 via the battery cell 100 fixed to the spacer 150. The bar portion 161 also has a protrusion 163 on the lower surface 162. The protrusion 163 is provided continuously along the bar portion 161 in the stacking direction of the battery cells 100. Figure 2 shows the dimension L1 of the bar portion 161. Dimension L1 is the length of the bar portion 161, including the protrusion 163, in the height direction of the battery cell 100.

3 shows the opposite side of the recess 151 of the spacer 150. As shown in FIG. 3, the sealing portion 160 has a hollow portion 171 on the opposite side of the bar portion 161. The hollow portion 171 has a space 172 extending in the stacking direction of the battery cells 100. The space 172 of the hollow portion 171 is a location into which the bar portion 161 of another spacer 150 is pressed in the battery stack 10. FIG. 3 shows the dimension L2 of the hollow portion 171. The dimension L2 is the length of the space 172 in the height direction of the battery cell 100. The dimension L2 of the space 172 of the hollow portion 171 is smaller than the dimension L1 of the bar portion 161. Therefore, when the bar portion 161 is pressed into the space 172, the hollow portion 171 is deformed so as to expand in the height direction of the battery cell 100.

A fin portion 174 is provided on the lower surface 173, which is located on the lower side of the outer surface of the hollow portion 171. The fin portion 174 is provided continuously along the hollow portion 171 in the stacking direction of the battery cells 100.

Figure 4 is a cross-sectional view of the battery pack 1 in the width direction. Only one of the two battery stacks 10 in the battery pack 1 is shown in Figure 4. The case member 200 has a side inner wall surface 202 and a bottom inner wall surface 203 as inner wall surfaces 201 that form the storage space 21. The bottom inner wall surface 203 is the upper surface of the floor portion 210. The bottom inner wall surface 203 is a surface that forms the lower side of the storage space 21. The side inner wall surface 202 is a surface that forms both ends of the storage space 21 in the width direction of the battery cell 100. In other words, there are two side inner wall surfaces 202 for one storage space 21. In addition, these two side inner wall surfaces 202 face each other. In the battery pack 1 of this embodiment, the cooling passage 300 is provided between the bottom inner wall surface 203 of the case member 200 and the lower surface 12 of the battery stack 10.

In this embodiment, the bottom inner wall surface 203 of the case member 200 is provided with a ventilation groove 240 extending in the stacking direction of the battery cells 100 at the cooling passage 300. The ventilation groove 240 extends from the end panel 250 side to the end wall portion 220. In the battery pack 1, the battery cells 100 are cooled by air flowing through the cooling passage 300. This suppresses the temperature rise of the battery cells 100.

As shown in FIG. 4, the bottom inner wall surface 203, which is the upper surface of the floor portion 210 of the case member 200, is provided with two alignment rail portions 230 extending in the stacking direction of the battery cells 100. The alignment rail portions 230 extend from the end panel 250 side to the end wall portion 220. The ventilation groove 240 is located between the two alignment rail portions 230.

The two alignment rail portions 230 are located slightly inside the two alignment protrusions 153 of the spacer 150 in the width direction of the battery cell 100. Therefore, when the spacer 150 rotates so that one of the two alignment protrusions 153 moves further in the stacking direction of the battery cells 100 than the other, the alignment protrusions 153 come into contact with the alignment rail portion 230. In other words, the alignment protrusions 153 fit into the alignment rail portion 230, preventing the spacer 150 and the battery cell 100 from rotating around a rotation axis extending in the height direction of the battery cell 100 relative to the case member 200.

The ventilation groove 240 has two groove side surfaces 241 positioned opposite each other, and a groove bottom surface 242 connecting the two groove side surfaces 241. Both the groove side surfaces 241 and the groove bottom surface 242 are part of the bottom inner wall surface 203 of the case member 200. The width direction and depth direction of the ventilation groove 240 are the same as the width direction and height direction of the battery cell 100, respectively.

As shown in FIG. 4, in the battery pack 1, both of the two seal portions 160 of the spacer 150 are located between the two groove side surfaces 241 of the ventilation groove 240. The bar portion 161 is pressed into the hollow portion 171 of the seal portion 160. The bar portion 161 is pressed into the hollow portion 171 so that the bar portion 161 is pressed against the inner surface of the hollow portion 171. The bar portion 161 pressed into the hollow portion 171 is the bar portion 161 of another spacer 150 adjacent to the spacer 150 having the hollow portion 171 via the battery cell 100. The protrusion 163 of the bar portion 161 is provided in the center of the width direction of the battery cell 100. On the other hand, the fin portion 174 of the hollow portion 171 is provided in the base portion 175, which is a portion on the outer side of the protrusion 163 in the width direction of the battery cell 100. Therefore, in the pressed-in state where the bar portion 161 is pressed in, the base portion 175 of the hollow portion 171 is displaced in a manner that causes the fin portion 174 to swing, compared to the non-pressed-in state where the bar portion 161 is not pressed in. The displacement of the base portion 175 of the hollow portion 171 is in a direction that brings the tip 176 of the fin portion 174 closer to the groove side surface 241.

In this embodiment, the two hollow portions 171 are displaced so that the tips 176 of the two fin portions 174 are opened in the width direction of the ventilation groove 240. As a result, the spacer 150 has the tips 176 of the two fin portions 174 in contact with different groove side surfaces 241. That is, for two spacers 150 adjacent to each other through a battery cell, the gap between the lower surface 12 of the battery stack 10 and the ventilation groove 240 is blocked by the seal structure 170 composed of the bar portion 161 on one side and the hollow portion 171 and fin portion 174 on the other side. That is, the cooling passage 300 is formed between the fin portions 174 of the two sets of seal structures 170 between the ventilation groove 240 provided on the bottom inner wall surface 203 of the case member 200 and the lower surface 12 of the battery stack 10. In addition, in the cooling passage 300, the tip 176 of the fin portion 174 is in contact with the groove side surface 241, so that the air flowing through the cooling passage 300 in the stacking direction of the battery cells 100 is prevented from leaking in the width direction of the battery cells 100.

In the battery stack 10, when the bar portion 161 is pressed into the hollow portion 171, the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100 are in close contact with each other so that no gaps are formed between them. This prevents air flowing through the cooling passage 300 from leaking between the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100. Alternatively, the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100 may each have an overlap portion that overlaps with the adjacent fin portion 174. This makes it possible to more appropriately prevent air from leaking from the cooling passage 300.

Figure 5 shows the hollow portion 171 before the bar portion 161 is pressed into the space 172. As shown in Figure 5, in the spacer 150, in the non-pressed state before the bar portion 161 is pressed into the hollow portion 171, the tip 176 of the fin portion 174 is not in contact with the case member 200, and a gap is formed between them. In the seal structure 170, the bar portion 161 is pressed into the hollow portion 171, which puts the hollow portion 171 into a deformed pressed-in state, and as shown in Figure 4, the tip 176 of the fin portion 174 comes into contact with the groove side surface 241 of the ventilation groove 240 of the case member 200.

Next, the manufacturing method of the battery pack 1 of this embodiment will be described with reference to Figures 6 and 7. Figure 6 is a diagram showing the battery stack 10, case member 200, and end panel 250 before they are assembled. Figure 7 is a diagram showing the battery stack 10, case member 200, and end panel 250 being assembled. Both Figures 6 and 7 are schematic diagrams showing a cross section taken along the line A-A in Figure 1. For example, Figures 6 and 7 omit details of the battery cells 100 and spacers 150 in the battery stack 10. In this embodiment, the battery pack 1 is manufactured by first housing the battery stack 10 in the case member 200, and then assembling the end panel 250.

As shown in FIG. 6, the battery stack 10 is constructed by stacking multiple assemblies of battery cells 100 and spacers 150 before being housed in the case member 200. As described above, the spacer 150 is provided with a seal portion 160 having a bar portion 161, a hollow portion 171, and a fin portion 174. The seal portion 160 faces downward. A first end plate 180 is stacked on the end of the battery stack 10 that faces the end panel 250. A second end plate 190 is stacked on the end of the battery stack 10 that faces the end wall portion 220.

In the stacking direction of the battery cells 100, the orientation of the multiple assemblies of the battery cells 100 and the spacers 150 is the same. In the battery stack 10 of this embodiment, the bar portion 161 faces the first end plate 180 side, and the hollow portion 171 faces the second end plate 190 side. In this embodiment, the second end plate 190 is provided with a bar portion 161 that is pressed into the hollow portion 171 of the spacer 150 located closest to the second end plate 190 in the stacking direction of the battery cells 100. In addition, the spacer 150 located closest to the first end plate 180 in the stacking direction of the battery cells 100 does not have a bar portion 161. This is because there is no other spacer 150 that has a hollow portion 171 into which the bar portion 161 is pressed. The spacer 150 located closest to the first end plate 180 may be provided with a bar portion 161.

In the battery stack 10 before being housed in the case member 200, the seal structure 170 is in a non-pressed state. That is, in the battery stack 10 before assembly, the bar portion 161 of one of the two spacers 150 adjacent to each other via the battery cell 100 is not pressed into the hollow portion 171 of the other spacer 150. Therefore, the distance between the spacers 150 is wider in the non-pressed state of the seal structure 170 than when it is in the pressed state. Then, as shown in FIG. 6, the battery stack 10 is assembled into the case member 200 by housing the battery stack 10 inside the case member 200 from the side of the mounting portion 226 of the end panel 250 of the case member 200.

The battery stack 10 can be accommodated in the case member 200 by moving at least one of the battery stack 10 or the case member 200 toward the other. In this embodiment, while the case member 200 is fixed, the battery stack 10 is pressed from the first end plate 180 side by the pressing part 400 as shown in FIG. 7(A). The part pressed by the pressing part 400 is the pressed part 183 of the first end plate 180. This causes the battery stack 10 to move toward the end wall part 220 and be accommodated in the case member 200 until the second end plate 190 comes into contact with the end wall part 220.

When the battery stack 10 is accommodated in the case member 200, the battery stack 10 moves along the bottom inner wall surface 203 of the case member 200. As described above, the bottom inner wall surface 203 of the case member 200 is provided with an alignment rail portion 230, and the spacer 150 of the battery stack 10 is provided with an alignment protrusion portion 153 that fits into the alignment rail portion 230. This makes it possible to prevent the battery cells 100 and the spacer 150 from rotating in the case member 200 when the battery stack 10 is accommodated in the case member 200. In other words, the battery stack 10 can be smoothly accommodated in the case member 200 without meandering in the stacking direction of the battery cells 100.

As shown in FIG. 7(A), in this embodiment, the bar portion 161 is not pressed into the hollow portion 171 until the battery stack 10 is accommodated in the case member 200 from the outside of the case member 200 and the second end plate comes into contact with the end wall portion 220. In other words, the seal structure 170 is maintained in a non-pressed state until the battery stack 10 enters the case member 200 from the outside of the case member 200 and comes into contact with the end wall portion 220. Therefore, as described in FIG. 5, the fin portion 174 of the seal structure 170 can be kept in contact with the case member 200 without contacting the case member 200, and the battery stack 10 can be accommodated in the case member 200 until it comes into contact with the end wall portion 220.

The battery stack 10 that has come into contact with the end wall portion 220 is further pressed by the pressing portion 400. That is, the second end plate 190 on the opposite side of the battery stack 10 to the side receiving the pressure is pressed against the end wall portion 220, while being compressed in the stacking direction of the battery cells 100. This pressing applies a compressive load to the battery stack 10 in the stacking direction of the battery cells 100.

In addition, by continuing to press the battery stack 10 by the pressing portion 400 even after the second end plate contacts the end wall portion 220, the sealing structure 170 is pressed in as shown in FIG. 7B. That is, for two spacers 150 adjacent to each other through the battery cell 100, the bar portion 161 provided on one side is pressed into the hollow portion 171 provided on the other side. This causes the hollow portion 171 to deform, and the tip 176 of the fin portion 174 can be brought into contact with the groove side surface 241. Thus, the cooling passage 300 described in FIG. 4 can be formed. In addition, by the sealing structure 170 being in the pressed-in state, the distance between the spacers 150 becomes narrower than in the non-pressed state before the pressed-in state.

The end panel 250 is attached to the mounting portion 226 while the pressing portion 400 is applying a compressive load to the battery stack 10. The end panel 250 can be attached to the mounting portion 226 by pressing the upper surface portion 251 toward the mounting portion 226. The end panel 250 has a clearance portion 252 formed at the location of the pressing portion 400, so that it does not interfere with the pressing portion 400.

Then, the pressure applied by the pressing unit 400 is released. When the pressure applied by the pressing unit 400 is released, the battery stack 10, which has been compressed and shrunk in the stacking direction of the battery cells 100, expands. Thus, the first end plate 180 of the battery stack 10, which has been released from compression, comes into contact with the end panel 250. This completes the manufacture of the battery pack 1. After that, the bus bar 30 is attached to the battery stack 10 of the battery pack 1 as appropriate.

After the battery stack 10 is released from the compressed state, even if it expands to contact the end panel 250, it is in a state that is smaller than the uncompressed state before being accommodated in the case member 200. That is, each battery cell 100 in the battery stack 10 is in a compressed state in the stacking direction. Therefore, the battery stack 10 in the battery pack 1 is sandwiched between the end wall portion 220 and the end panel 250. As a result, the battery stack 10 is held in the storage space 21 of the battery case 20. In addition, the end panel 250 in the battery pack 1 is pressed against the outer surface of the groove-shaped mounting portion 226 in the stacking direction of the battery cells 100 in a direction away from the end wall portion 220 by the compression reaction force of the battery stack 10. As a result, the end panel 250 is prevented from falling off the mounting portion 226. Therefore, the battery stack 10 and the end panel 250 are appropriately prevented from falling off the case member 200. In other words, no special fastening or joining is required to secure the battery stack 10 or the end panel 250. Therefore, the battery pack 1 requires fewer parts, which reduces manufacturing costs.

In addition, in this embodiment, as described above, the battery stack 10 can be housed in the case member 200 until it contacts the end wall portion 220 without contacting the fin portion 174 of the seal structure 170 with the case member 200. This can prevent the fin portion 174 from interfering with the case member 200. In other words, damage to the fin portion 174 and the case member 200 can be prevented. After the battery stack 10 is housed in the case member 200 until it contacts the end wall portion 220, the seal structure 170 can be pressed in to form the cooling passage 300. This allows the cooling passage 300 to be appropriately formed using a spacer 150 with a simple configuration.

Note that, for example, unlike this embodiment, it is also possible to adopt a seal structure using an elastic member such as a sponge instead of the seal structure 170. Specifically, for example, it is possible to fix a sponge of a height sufficient to contact the lower surface of the battery stack to the bottom inner wall surface of the case member. Note that, in order to ensure a certain degree of airtightness using the sponge, the height of the sponge needs to be such that the sponge is pressed against the lower surface of the battery stack. However, in such a configuration, when the battery stack is moved in the stacking direction of the battery cells and housed in the case member, the sponge and the battery stack come into contact with each other. The sponge that comes into contact with the battery stack may peel off from the case member or may be damaged. In addition, since the frictional resistance of the sponge tends to be large, the battery cells may fall over when the battery stack is housed in the case member. In contrast, in this embodiment, after the battery stack 10 is housed in the case member 200, the fin portion 174 can be brought into contact with the inner wall surface 201 of the case member 200. Therefore, in the battery pack 1 of this embodiment, the above-mentioned problems that occur when a seal structure such as a sponge is adopted do not occur.

In addition, the case member 200 of this embodiment has a ventilation groove 240 on the bottom inner wall surface 203. The spacer 150 has a fixing surface 152 that fixes the adjacent battery cells 100 in the width direction. The width direction of the battery cells 100 is the same as the width direction of the ventilation groove 240. Furthermore, the two sets of seal structures 170 related to the spacer 150 have the two fin parts 174 in contact with the different groove side surfaces 241 of the two groove side surfaces 241 of the ventilation groove 240 at their tips 176 when the bar part 161 is pressed into the hollow part 171. In other words, when the two sets of seal structures 170 are pressed into the hollow part 171, the two fin parts 174 receive reaction forces from the different groove side surfaces 241 that face each other. These reaction forces allow the positions of all the battery cells 100 in the width direction to be stably determined with respect to the ventilation groove 240. In other words, the battery cells 100 can be aligned without meandering in the stacking direction. In addition, by increasing the cross-sectional area of the cooling passage 300 using the ventilation grooves 240, the flow rate of air flowing through the cooling passage 300 can be made sufficient.

In this embodiment, the spacer 150 has a base 175 on which the fin portion 174 is provided in the hollow portion 171, which displaces so as to swing the fin portion 174 when the bar portion 161 is pressed into the hollow portion 171. Therefore, the amount of displacement of the base 175 can be small. That is, the amount of movement of the tip 176 of the fin portion 174 can be secured large while suppressing deformation of the hollow portion 171. This can reduce the pressing force required to press the bar portion 161 into the hollow portion 171. In addition, the amount of deformation of the hollow portion 171 can be reduced, and damage thereto can be suppressed. Furthermore, by ensuring a large amount of movement of the tip 176 of the fin portion 174, a sufficient clearance can be secured between the fin portion 174 and the case member 200 when the battery stack 10 is inserted into the case member 200. Also, for example, if the hollow portion 171 into which the bar portion 161 is press-fitted is significantly deformed, the movement of the fin portion 174 toward the inner wall surface 201 of the case member 200 will also be large. Even in such a case, the fin portion 174 that has moved in a swinging manner can be deformed so as to bend overall when it comes into contact with the side inner wall surface 202. This makes it possible to prevent damage to the seal structure 170, etc., and to properly form the cooling passage 300.

As described above in detail, according to this embodiment, the battery pack 1 has a battery stack 10 and a battery case 20. The battery stack 10 is formed by stacking a plurality of battery cells 100 with spacers 150 interposed therebetween. The battery case 20 accommodates the battery stack 10 from the mounting portion 226 side of the end panel 250, which is one end side in the stacking direction of the battery cells 100. In the battery pack 1, a cooling passage is provided between the bottom inner wall surface 203 of the case member 200 constituting the battery case 20 and the battery stack 10, through which air for cooling the battery cells 100 passes in the stacking direction of the battery cells 100. The spacer 150 has two sets of seal structures 170 consisting of a bar portion 161, a hollow portion 171, and a fin portion 174 for two adjacent spacers 150 adjacent to each other through the battery cells 100. The bar portion 161 is provided on one spacer 150 and extends in the stacking direction of the battery cells 100 toward the other spacer 150 side. The hollow portion 171 is provided in the other spacer 150, and a space 172 extending in the stacking direction of the battery cells 100 is formed, and the bar portion 161 provided in one spacer 150 is press-fitted into the space 172. The fin portion 174 is provided on a lower surface 173 of the outer surface of the hollow portion 171, and a tip 176 is in contact with a bottom inner wall surface 203 of the case member 200. The cooling passage 300 is formed between the fin portions 174 of the two sets of seal structures 170 between the bottom inner wall surface 203 of the case member 200 and the battery stack 10. In a non-press-fit state in which the bar portion 161 is not press-fitted into the hollow portion 171, the tip 176 of the fin portion 174 of the spacer 150 does not contact the inner wall surface 201 of the case member 200. On the other hand, in a press-fit state in which the hollow portion 171 is deformed by pressing the bar portion 161 into the hollow portion 171, the tip 176 comes into contact with the bottom inner wall surface 203 of the case member 200. Then, the battery pack 1 is inserted into the case member 200 by pressing the battery stack 10 from the first end plate 180 side in a state in which the bar portion 161 is not pressed into the hollow portion 171. Furthermore, the bar portion 161 is pressed into the hollow portion 171 while applying a compressive load to the battery stack 10 in the stacking direction of the battery cells 100. This forms the cooling passage 300 of the battery pack 1. The spacer 150 does not have a complex seal structure 170 for forming the cooling passage 300. In other words, the configuration for providing the cooling passage 300 is simple, and the cost of each component can be reduced. This realizes a battery pack 1 and a manufacturing method thereof that can reduce manufacturing costs.

The embodiments and examples described above are merely examples and do not limit the disclosed technology in any way. Naturally, the disclosed technology can be improved and modified in various ways without departing from the spirit of the technology.

For example, in the above embodiment, the mounting portion for mounting the end panel is described as being configured with a single groove-shaped mounting portion. However, the mounting portion of the end panel may be provided with multiple mounting portions each located at a different position in the stacking direction of the battery cells. The end panel may be attached to one of the multiple mounting portions depending on the length of the battery stack in the stacking direction of the battery cells in the compressed state. The relationship between the length of the battery stack in the compressed state and the mounting portion for mounting the end panel may be determined in advance. In this way, a battery pack in which the battery stack is appropriately compressed in the stacking direction of the battery cells can be obtained. In addition, the reaction force that the end panel receives from the battery stack can be made appropriate.

In the above embodiment, the tip of the fin portion of the seal structure is described as contacting the bottom inner wall surface of the case member. However, for example, the location where the tip of the fin portion contacts may be the inner wall surface of the case member, or may be the side inner wall surface. In the above embodiment, an example was described in which a groove portion is provided at the location of the cooling passage on the inner wall surface of the case member. However, for example, the location of the cooling passage of the case member may be a flat inner wall surface without a groove portion, in which case the fin portion of the seal structure in the pressed state may be configured to contact the flat inner wall surface.

In the above embodiment, an example was described in which the battery cell was attached to the spacer on the end wall side of the battery cell. However, the battery cell may also be attached to the spacer on the end panel side of the battery cell. In the above embodiment, the same spacer was used, and the cooling passage was described as being formed continuously from the end panel side to the end wall side. However, for example, a configuration can be adopted in which a spacer without fins is provided in some parts, and the cooling passage is branched at that position.

For example, when the battery stack is housed in the case member, the bar portion may have a part of its tip inserted into the space of the hollow portion before the battery stack abuts against the end wall portion, so long as the fin portion does not come into contact with the inner wall surface of the case member. Then, when the battery stack abuts against the end wall portion, the bar portion may be pressed into the hollow portion, and the tip of the fin portion may come into contact with the inner wall surface of the case member.

In the above embodiment, the deformation portion of the spacer that is deformed by the pressure contact of the bar portion is a hollow portion with a space formed inside. However, the deformation portion that is deformed by the pressure contact of the bar portion does not necessarily have to be hollow. In other words, the deformation portion provided with the fin portion may be deformed by the pressure contact of the bar portion, and the fin portion may be brought into contact with the inner wall surface of the case member. Specifically, for example, a spacer in which the two hollow portions according to the above embodiment are replaced with two deformation portions having a shape in which the wall surfaces located on the inside in the width direction of the battery cell are removed from the two hollow portions may be used. Even in a spacer in which the deformation portions are replaced with such hollow portions, the fin portion can be changed from a non-pressed state before the bar portion is pressed against the deformation portion to a pressed state in which the bar portion is pressed against the deformation portion and the deformation portion is deformed, so that the fin portion can be changed from a state in which the fin portion is not in contact with the inner wall surface of the case member to a state in which the fin portion is in contact. Note that by adopting a shape like the hollow portion according to the above embodiment as the deformation portion, it is possible to make it difficult for deformation due to vibration or the like to occur before the bar portion is pressed into the deformation portion. In other words, it is possible to suppress vibration of the fin portion and more reliably prevent the fin portion from coming into contact with the case member when the battery stack is inserted into the case member. And even if the deformation portion has a hollow shape, it can be easily deformed by pressing in the bar portion.

In the above embodiment, the sealing structure is described as an example in which a protrusion is formed on the bar portion, and the hollow portion is flat at the point where the protrusion of the bar portion comes into contact. However, for example, a protrusion protruding toward the bar portion may be provided within the space of the hollow portion, and the bar portion may have no protrusion. In other words, the shape of the bar portion and hollow portion may be configured such that the hollow portion is deformed when the bar portion is pressed in, and as a result, the fin portion provided on the outer surface of the hollow portion moves so that its tip comes into contact with the inner wall surface of the case member.

For example, the fluid flowing through the cooling passage is not limited to air, and may be a gas other than air. Furthermore, there are no particular limitations on the type of battery (nickel-metal hydride battery, lithium-ion battery, etc.) to which the above embodiment can be applied.

Reference Signs List 1 Battery pack 10 Battery stack 12 Underside 20 Battery case 100 Battery cell 150 Spacer 161 Bar portion 170 Sealing structure 171 Hollow portion 174 Fin portion 176 Tip 200 Case member 203 Bottom inner wall surface 240 Ventilation groove 241 Groove side surface 250 End panel 300 Cooling passage

Claims (10)

A battery pack comprising: a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween; and a case that houses the battery stack from one end side in a stacking direction of the battery cells, the battery pack having a cooling passage between an inner wall surface of the case and the battery stack, the cooling passage allowing a fluid for cooling the battery cells to pass in the stacking direction,
The spacer is arranged such that two adjacent spacers are spaced apart from each other by the battery cell.
A bar portion provided on one side and extending toward the other side in the stacking direction;
a deformation portion provided on the other side and deformed by the bar portion provided on the one side being pressed against the deformation portion;
a fin portion provided at the deformation portion and having a tip in contact with an inner wall surface of the case;
The battery pack, wherein the cooling passage is formed between the fin portions of the two sets of the seal structures between the inner wall surface of the case and the battery stack. 2. The battery pack according to claim 1,
a groove portion extending in the stacking direction is provided in an inner wall surface of the case at a location of the cooling passage,
The spacer is
a fixing portion that fixes adjacent battery cells in a width direction of the groove portion;
A battery pack in which the tips of the fin portions of the two sets of the sealing structures are respectively in contact with different of two opposing side surfaces of the groove portion. The battery pack according to claim 1 or 2,
The deformation portion is deformed by the bar portion being pressed against the battery pack so as to swing the fin portion compared to when the bar portion is not pressed against the battery pack. The battery pack according to claim 1 or 2,
The deformation portion has a space extending in the stacking direction, and the bar portion is press-fitted into the space, thereby causing the battery pack to deform. The battery pack according to claim 1 or 2,
The case is
a floor portion located below the battery stack;
An end panel attached to one end side in the stacking direction;
an end wall portion that is located on the other end side opposite to the attachment point of the end panel and is integral with the floor portion;
The battery stack is a battery pack that is held in the case while being sandwiched between the end panel and the end wall portion. A method for manufacturing a battery pack comprising: a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween; and a case that houses the battery stack from one end side in a stacking direction of the battery cells, the battery pack having a cooling passage between an inner wall surface of the case and the battery stack, the cooling passage allowing a fluid for cooling the battery cells to pass in the stacking direction, the method comprising the steps of:
As the spacer, two adjacent spacers disposed between the battery cells are
A bar portion provided on one side and extending toward the other side in the stacking direction;
a deformation portion provided on the other side and deformed by pressure contact with the bar portion provided on the one side;
a fin portion provided on the deformation portion, the fin portion having a tip that does not contact the inner wall surface of the case in a non-pressure-contact state where the bar portion is not pressed against the deformation portion, and a tip that contacts the inner wall surface of the case in a pressurized state where the bar portion is pressed against the deformation portion and the deformation portion is deformed,
The battery stack is inserted into the case from one end side by pressing the battery stack from the one end side with the bar portion not being pressed against the deformation portion, and the bar portion is pressed against the deformation portion while applying a compressive load in the stacking direction to the battery stack;
A manufacturing method for a battery pack in which the bar portion is pressed against the deforming portion, thereby bringing the tip of the fin portion into contact with the inner wall surface of the case, thereby forming the cooling passage between the fin portions of two sets of the sealing structure between the inner wall surface of the case and the battery stack. A method for manufacturing a battery pack according to claim 6, comprising the steps of:
The case has an inner wall surface provided with a groove extending in the stacking direction at a location of the cooling passage,
As the spacer,
a fixing portion that fixes adjacent battery cells in a width direction of the groove portion;
A manufacturing method for a battery pack in which, with the bar portion pressed against the deformation portion, the tips of the fin portions of the two sets of the sealing structures are brought into contact with different of the two opposing side surfaces of the groove portion. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of:
A manufacturing method for a battery pack using as the spacer a portion of the deformation portion where the fin portion is provided that displaces so as to oscillate the fin portion when it changes from the non-pressurized state to the pressed state. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of:
A method for manufacturing a battery pack using the spacer in which the deformation portion has a space extending in the stacking direction and the bar portion is pressed into the space to deform. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of:
In the above case,
a floor portion located below the battery stack;
An end panel attached to one end side in the stacking direction;
and an end wall portion that is connected to the floor portion and is integral with the end panel, the end wall portion being located on the other end side opposite to the attachment point of the end panel.
by pressing the battery stack from one end side in a state in which the bar portion is not pressed against the deformation portion, the other end side of the battery stack is pressed against the end wall portion, and the bar portion is pressed against the deformation portion while applying a compressive load in the stacking direction to the battery stack;
Attaching the end panel to the case;
A method for manufacturing a battery pack, comprising releasing the pressure on one end side of the battery stack and bringing one end side in the stacking direction into contact with the end panel, thereby causing the battery stack to be held in the case while being sandwiched between the end wall portion and the end panel.

Images