Battery module manufacturing method, battery module, and pressing device for battery module

Abstract

In an aligning step, a plurality of battery cells (110) aligned with one or more intermediate plates interposed therebetween are sandwiched between two end plates (131) from the front and rear. In a pressing step, a pressing force is measured while the plurality of battery cells (110) are pressed by the force applied to the two end plates (131) in the longitudinal direction. In a fixing step, the two end plates (131) are fixed with a spacing when the pressing force becomes equal to a set value, using one or more through bolts (141) that are inserted into through holes formed on the sides of the intermediate plates and through holes formed on the sides of the end plates (131), and nuts (142) for the through bolts (141).

Description

Method for manufacturing battery module, battery module, and pressing device for battery module

[0001] The present disclosure relates to a method for manufacturing a battery module.

[0002] Conventionally, in order to manufacture a battery for realizing a battery pack, a plurality of battery cells are pressed and fixed. When the battery is used in outer space, it is necessary to fix a plurality of battery cells so as to withstand the vibration at the time of launch.

[0003] Patent Document 1 discloses a battery module technology. In this technology, the fixing position of the holder is adjusted so that the rigidity of each battery cell becomes high, and assembly is performed while securing a certain pressing force. The fixing position of the holder is adjusted using a shim. A shim is a component for adjusting the pressing force. A plurality of battery cells are fixed by a chassis and a holding plate using a holding plate for pressing the battery cells.

[0004] The technology of Patent Document 1 requires measuring the mechanical characteristics of each battery cell before assembly in order to select a shim corresponding to the mechanical characteristics of the battery cell. That is, it takes a lot of man-hours for measurement. In addition, since it is necessary to prepare a shim for each mechanical characteristic of the battery cell, the number of parts increases.

[0005] International Publication No. 2018 / 008135

[0006] An object of the present disclosure is to enable manufacturing of a battery module while suppressing the number of working hours and the number of parts.

[0007] The battery module manufacturing method of this disclosure comprises: an alignment step of sandwiching a plurality of battery cells, which are aligned with one or more intermediate plates in between, between two end plates from the front and rear; a pressing step of applying force to the two end plates from the front and rear directions to press the plurality of battery cells and measuring the pressing force; and a fixing step of fixing the two end plates at an interval when the pressing force becomes equal to a set value, using one or more through bolts that pass through through holes in the sides of each intermediate plate and through holes in the sides of each end plate, and nuts for each of the through bolts.

[0008] According to this disclosure, it is possible to manufacture battery modules while reducing the amount of work required and the number of parts.

[0009] External view of the battery module 100 in Embodiment 1. View of the battery module 100 from below in Embodiment 1. Diagram showing the inside of the battery module 100 in Embodiment 1. Diagram showing the intermediate plates (121, 122) in Embodiment 1. Cross-sectional view of the battery module 100 in Embodiment 1. Flowchart of the battery module manufacturing method in Embodiment 1. Diagram showing the inside of the battery cell 110 in Embodiment 1. Configuration diagram of the battery module pressing device 200 in Embodiment 1.

[0010] In the embodiments and drawings, the same or corresponding elements are denoted by the same reference numeral. The descriptions of elements denoted by the same reference numeral as the described elements are omitted or simplified as appropriate.

[0011] Embodiment 1. A battery module manufacturing method will be described based on Figures 1 to 8.

[0012] ***Explanation of Configuration*** The configuration of the battery module 100 will be explained based on Figures 1 to 5. The battery module 100 is the smallest component unit of a battery pack. A battery pack is composed of one or more battery modules 100 combined together.

[0013] Figure 1 shows the external appearance of the battery module 100. The battery module 100 comprises a plurality of battery cells 110. In Figure 1, the battery module 100 has six battery cells 110. However, the number of battery cells 110 may be five or fewer, or seven or more.

[0014] Figure 2 shows the battery module 100 viewed from below. Multiple battery cells 110 are arranged with one or more intermediate plates (121, 122) in between. Two battery cells adjacent to each other front and back (110A, 110B) are called a battery cell set. In Figure 2, the battery module 100 has three battery cell sets. In each battery cell set, two battery cells are arranged in opposite directions with their electrodes facing each other. In Figure 2, battery cells 110A and 110B are arranged in opposite directions with their electrodes facing each other. In Figure 1, the six battery cells 110 are arranged alternately in opposite directions. In each battery cell set, a retaining plate 121 is placed between two battery cells. In Figure 2, for each set of battery cells 110A and 110B, a retaining plate 121 is placed between battery cells 110A and 110B. For every pair of battery cell sets that are adjacent to each other, a partition plate 122 is placed between the two battery cell sets. In Figure 2, for every pair of battery cell sets 110A and 110B, a partition plate 122 is placed between battery cell 110B and battery cell 110A.

[0015] In Figure 1, the battery module 100 includes two end plates 131. The two end plates 131 sandwich a plurality of battery cells 110 from the front and back.

[0016] The battery module 100 is equipped with one or more through bolts 141. In Figure 1, the battery module 100 is equipped with four through bolts 141. However, the number of through bolts 141 may be three or fewer, or five or more. The battery module 100 is equipped with two nuts 142 for fixing the front and rear end plates 131 to each through bolt 141.

[0017] Figure 3 shows the inside of the battery module 100. Each end plate 131 has a through hole on its side through which a through bolt 141 is passed. Each intermediate plate (121, 122) has a through hole on its side through which a through bolt 141 is passed.

[0018] Each through bolt 141 is passed through the through hole in each intermediate plate and through the through hole in each end plate 131. Each intermediate plate is secured to the through bolt 141 using a nut. The two end plates 131 are secured using through bolts 141 and nuts 142 at intervals that press against multiple battery cells 110.

[0019] Figure 4 shows a battery cell 110B. The battery cell 110B is sandwiched between a retaining plate 121 and a partition plate 122. At least one of the intermediate plates (121, 122) has a recess 123 in the portion facing the battery cell 110. In Figure 4, the partition plate 122 has the recess 123. However, the retaining plate 121 may have the recess 123 instead of the partition plate 122, or it may have the recess 123 together with the partition plate 122. A heater 124 is attached to the recess 123. For example, a sheet-shaped heater 124 is attached to the recess 123. The heater 124 is used to suppress the temperature drop of the battery module 100.

[0020] Figure 5 shows a cross-section of the battery module 100. In Figure 5, each partition plate 122 has recesses 123 on the top and bottom of both sides, and a heater 124 is attached to each recess 123. Furthermore, each end plate 131 has recesses on the top and bottom of its inner surface, and a heater 124 is attached to each recess.

[0021] In Figure 1, the battery module 100 comprises two side plates (132, 133, 134). The two side plates surround and cover multiple battery cells 110 from the left and right. The side plates consist of an upper side plate 132, a middle side plate 133, and a lower side plate 134. Each side plate is fixed to the end plate 131 and the intermediate plate using bolts 135.

[0022] ***Configuration Notes*** If a large output is required, multiple battery modules 100 are connected together.

[0023] The battery module 100 is configured by connecting multiple battery cells 110 in series or in parallel.

[0024] The battery cell 110 is, for example, a lithium battery cell. The cross-sectional shape of the battery cell 110 is an elongated ellipse. However, the cross-sectional shape of the battery cell 110 may be rectangular or circular, or any other shape.

[0025] The retaining plate 121 is lightweight. The retaining plate 121 can secure the battery cell assembly even if the battery cell 110 expands. This results in a battery case with high vibration resistance. The retaining plate 121 may be sized to hold only the middle portion of the battery cell 110, as shown in Figure 4, or it may be sized to hold the entire battery cell 110, similar to the partition plate 122 in Figure 4.

[0026] The end plate 131 and intermediate plates (121, 122) are made of aluminum. However, the end plate 131 and intermediate plates may be made of a metal other than aluminum.

[0027] The shapes of the components of the battery module 100 are not limited. For example, the shape of the end plate 131 may be a shape with multiple recesses formed therein, as shown in Figure 1, or it may be a grid shape with cavities instead of recesses. The end plate 131 may be a structure consisting only of a frame and beams, or only a frame. These shapes make the end plate 131 lighter. For example, the shapes of the upper side plate 132, the middle side plate 133, and the lower side plate 134 are not limited to the shapes shown in Figure 1.

[0028] ***Explanation of Operation*** Based on Figure 6, the battery module manufacturing method will be explained. The battery module manufacturing method may be performed manually, automated by equipment, or a combination of manual and automated methods.

[0029] Step S110 is a manufacturing process. In step S110, multiple battery cells 110 are manufactured.

[0030] Figure 7 shows a part of the inside of a battery cell 110. The battery cell 110 comprises an outer casing 111 and terminal electrodes 116 for each polarity. Figure 7 shows a terminal electrode 116 with one polarity, and the terminal electrode 116 with the other polarity is not shown. Inside the outer casing 111, the battery cell 110 comprises an electrode structure 112 and current collector plates 115 for each polarity. Figure 7 shows a current collector plate 115 with one polarity, and the current collector plate 115 with the other polarity is not shown. The electrode structure 112 includes two electrode plates 113 and two separators 114. The separators 114 are used to maintain the distance between two electrode plates 113 with different polarities. In Figure 7, electrode plates 113A and 113B have different polarities and different compositions. One separator 114 is sandwiched between electrode plates 113A and 113B. Another separator 114 is sandwiched between the outer casing 111 and the electrode plate 113B. The electrode structure 112 is a wound body in which two electrode plates 113 are wound around the separator 114. The current collector plate 115 is connected to the electrode plate 113. The terminal electrode 116 is connected to the current collector plate 115.

[0031] An electrolyte solution is injected into the outer container 111, and the electrode structure 112 is immersed in the electrolyte solution. Then, the charge generated by the electrochemical reaction is extracted from the terminal electrode 116 via the current collector plate 115.

[0032] Each battery cell 110 has variations in its thickness within the manufacturing tolerance. Each battery cell 110 also has variations in a value corresponding to its spring constant. This spring constant is a coefficient that determines the external force required to change the thickness of the battery cell 110.

[0033] Returning to Figure 6, we will continue the explanation from step S120. Step S120 is the charging process. In step S120, each battery cell 110 is charged. Each battery cell 110 is charged within a predetermined charge level range.

[0034] When the battery cell 110 is charged, it expands and its thickness increases compared to when it is not charged.

[0035] Step S130 is the heater installation process. In step S130, the heaters 124 are installed in the recesses 123 of each intermediate plate (122). Additionally, the heaters 124 are installed in the recesses of each end plate 131.

[0036] Step S140 is an alignment process. In step S140, multiple battery cells 110 are aligned with intermediate plates (121, 122) in between.

[0037] Multiple battery cells 110 are arranged as follows. Two battery cells (110A, 110B) that are adjacent to each other front and back are called a battery cell set. For each battery cell set, two battery cells (110A, 110B) are placed side by side with their electrodes facing in opposite directions, and a retaining plate 121 is sandwiched between the two battery cells. For each pair of battery cell sets that are adjacent to each other front and back, a partition plate 122 is sandwiched between the two battery cell sets. Each through bolt 141 is passed through the through holes in the end plate 131 and the intermediate plates (121, 122), respectively.

[0038] Step S150 is a pressing process. In step S150, force is applied to the two end plates 131 from the front and rear directions to press the multiple battery cells 110. The pressing force is measured at the same time.

[0039] A pressing device 200 for battery modules is used in the pressing process.

[0040] The battery module pressing device 200 will be described based on Figure 8. The battery module pressing device 200 comprises an outer shell 201, a support part 202, a cylinder 210, and a load cell 211. The support part 202 supports the front end plate 131 from the front. The cylinder 210 pushes the rear end plate 131 from rear to front. The load cell 211 measures the force applied from the cylinder 210 to the rear end plate 131 as the pressing force. In Figure 8, the load cell 211 is mounted on the cylinder 210.

[0041] The load cell 211 measures the pressing force, and the cylinder 210 increases the pressing force until it equals a set value. The set value is a predetermined value. For example, the load cell 211 has a display unit that displays the pressing force. The operator then increases the pressing force of the cylinder 210 until the displayed pressing force equals the set value. For example, the load cell 211 outputs information indicating the pressing force to the cylinder 210 or the cylinder control device. The cylinder 210 or the cylinder control device increases the pressing force of the cylinder 210 until it equals the set value.

[0042] Returning to Figure 6, we will continue the explanation from step S160. Step S160 is the fixing process. In step S160, each end plate 131 and each intermediate plate are fixed in place.

[0043] The two end plates 131 are fixed at an interval when the pressing force becomes the same as the set value, using a through bolt 141 and a nut 142. Each intermediate plate (121, 122) is fixed to the through bolt 141 using a nut. Each side plate (132, 133, 134) is fixed to the end plate 131 and the intermediate plate using a bolt 135.

[0044] Step S170 is an assembly process. In step S170, other components are attached to the battery module 100. For example, electrical wiring, a temperature sensor, etc. are attached to the battery module 100.

[0045] ***Effect of Embodiment 1*** In the following description, the reference numerals of the elements corresponding to the elements to be described are indicated in parentheses. Embodiment 1 relates to a method for manufacturing a battery (100) for a satellite.

[0046] Embodiment 1 aims to reduce the man-hours of the assembly work and the number of parts in the manufacture of a satellite battery.

[0047] In Embodiment 1, a pressure measuring instrument (211) is used, and a plurality of battery cells 110 are pressed together, and pressing and measurement are performed simultaneously.

[0048] According to Embodiment 1, it becomes possible to manufacture a satellite battery without measuring the mechanical characteristics of each cell (110). Also, parts (shims) for adjusting the pressing force become unnecessary.

[0049] In Embodiment 1, a satellite battery is assembled while managing the pressing force, and it is not necessary to give excessive pre-tension to the through bolt (141). Therefore, the diameter of the through bolt can be reduced to reduce the weight of the satellite battery.

[0050] Since the manufacturing process is simplified by Embodiment 1, it becomes easy to realize the assembly of a satellite battery with an automatic machine.

[0051] ***Summary of Embodiment 1*** The battery module 100 comprises the following elements: One end plate 131 and the other end plate 131. Multiple through bolts 141 that pass through each end plate 131 and connect the one end plate 131 and the other end plate 131. A partition plate 122 positioned between the one end plate 131 and the other end plate 131, having multiple holes into which the through bolts 141 are inserted. A retaining plate 121 positioned between the one end plate 131 and the other end plate 131, having multiple holes into which the through bolts 141 are inserted. A battery cell 110 positioned between the partition plate 122 and the retaining plate 121. The battery cell 110 is pressed by the end plates 131 at both ends and held between the partition plate 122 and the retaining plate 121.

[0052] The battery cell 110 is pressed by the end plates 131 on each side and fixed using through bolts 141 and nuts 142 that pass through the end plates 131.

[0053] The partition plate 122 is provided with a recess 123, and a heater 124 is placed in the recess 123.

[0054] The thickness of the heater 124 is thinner than the thickness of the partition plate 122 (specifically, the recess 123).

[0055] The battery module 100 includes a plurality of retaining plates 121 and a plurality of partition plates 122 between the end plates 131. Between the end plates 131, a battery cell 110, a retaining plate 121, a battery cell 110, a partition plate 122, a battery cell 110, a retaining plate 121, and a battery cell 110 are arranged in that order.

[0056] The end plate 131 has a cavity or recess formed in the middle. Alternatively, the end plate 131 can constitute the structure using only beams.

[0057] The end plate 131 corresponds to the chassis of the battery module 100. The side plates are fixed to the end plate 131 with screws, and the end plate 131 and the side plates constitute the chassis.

[0058] The battery module manufacturing method includes the following steps. The battery pressurizing device corresponds to the cylinder 210, and the pressure measuring device corresponds to the load cell 211. Steps for manufacturing the battery cell 110. The battery cell 110 has an outer casing 111. The outer casing 111 has a first main surface and a second main surface facing the first main surface. The battery cell 110 has two electrode plates 113 provided inside the outer casing 111, a current collector plate 115 connected to the electrode plates 113, and a terminal electrode 116 connected to the current collector plate 115. Alignment step. The second main surfaces of the battery cells 110 arranged at both ends of the battery module 100 are brought into contact with the end plates 131. The second main surfaces of the battery cells 110 that are not in contact with the end plates 131 are brought into contact with the partition plate 122. The holding plate 121 is brought into contact with the first main surface of the battery cell 110. Fixing step using a battery pressurizing device equipped with a pressure measuring device. The pressing force is applied while directly measuring and controlling the pressing force. The aligned battery cells 110, end plates 131, partition plates 122, and retaining plates 121 are fixed together by nuts 142 and through bolts 141. The number of battery cells 110 may be odd. If the number of battery cells 110 is odd, any battery cells 110 that are missing from the battery cell assembly are fixed by sandwiching them between the retaining plate 121 and the end plate 131 using the retaining plate 121 instead of the partition plate 122.

[0059] The battery module 100 is assembled with the battery cells 110 charged to a predetermined range (X to Y%) between 0 and 100%.

[0060] ***Supplement to Embodiment 1*** Embodiment 1 is an example of a preferred embodiment and is not intended to limit the technical scope of this disclosure. Embodiment 1 may be implemented in part or in combination with other embodiments. The procedure described using flowcharts may be modified as appropriate.

[0061] The following describes various aspects of this disclosure as appendices. (Appendix 1) A battery module manufacturing method comprising: an alignment step of sandwiching a plurality of battery cells, which are aligned with one or more intermediate plates in between, between two end plates from the front and rear; a pressing step of measuring the pressing force while applying force from the front and rear directions to the two end plates to press the plurality of battery cells; and a fixing step of fixing the two end plates at an interval when the pressing force becomes equal to a set value, using one or more through bolts that pass through through holes in the sides of each intermediate plate and through holes in the sides of each end plate, and nuts for each of the through bolts.

[0062] (Note 2) The battery module manufacturing method according to Note 1, wherein in the alignment step, for each set of two battery cells adjacent to each other in the front and back, the two battery cells are arranged in opposite directions, the holding plate which is the intermediate plate is placed between the two battery cells, and for each set of two battery cells adjacent to each other in the front and back, the partition plate which is the intermediate plate is placed between the two battery cell sets.

[0063] (Note 3) The battery module manufacturing method according to Note 1 or Note 2, wherein at least one of the intermediate plates has a recess in the portion facing the battery cell, and a heater mounting step is taken to attach heaters to each of the recesses for suppressing a decrease in the temperature of the battery module.

[0064] (Note 4) A battery module manufacturing method according to any one of Notes 1 to 3, comprising a charging step for charging each of the aforementioned battery cells, wherein the pressing step is performed when each of the aforementioned battery cells is charged and swollen.

[0065] (Note 5) A battery module manufacturing method in which a pressing device for battery modules is used in the pressing step, wherein the pressing device for battery modules comprises a support part that supports the front end plate from the front, a cylinder that pushes the rear end plate from the rear to the front, and a load cell that measures the force applied from the cylinder to the rear end plate as the pressing force, as described in any one of Notes 1 to 4.

[0066] (Note 6) A battery module comprising: a plurality of battery cells arranged in a line with one or more intermediate plates in between; two end plates sandwiching the plurality of battery cells from the front and rear; one or more through bolts passed through through holes in the sides of each intermediate plate and through holes in the sides of each end plate; and nuts used for each of the through bolts to fix the two end plates at intervals that press against the plurality of battery cells.

[0067] (Note 7) A pressing device for a battery module for pressing multiple battery cells of a battery module, wherein the battery module comprises: multiple battery cells arranged in a front-to-back line; and two end plates that sandwich the multiple battery cells from the front and back, and the pressing device for the battery module comprises: a support part that supports the front end plate from the front; a cylinder that pushes the rear end plate from the rear to the front; and a load cell that measures the force applied from the cylinder to the rear end plate as a pressing force.

[0068] 100 Battery module, 110 Battery cell, 111 Outer casing, 112 Electrode structure, 113 Electrode plate, 114 Separator, 115 Current collector plate, 116 Terminal electrode, 121 Retaining plate, 122 Partition plate, 123 Recess, 124 Heater, 131 End plate, 132 Upper side plate, 133 Middle side plate, 134 Lower side plate, 135 Bolt, 141 Through bolt, 142 Nut, 200 Pressing device for battery module, 201 Outer shell, 202 Support part, 210 Cylinder, 211 Load cell.

Claims

1. A battery module manufacturing method comprising: an alignment step of sandwiching a plurality of battery cells, which are aligned with one or more intermediate plates in between, between two end plates from the front and rear; a pressing step of applying force to the two end plates from the front and rear directions to press the plurality of battery cells and measuring the pressing force; and a fixing step of fixing the two end plates at an interval when the pressing force becomes equal to a set value, using one or more through bolts that pass through through holes in the sides of each intermediate plate and through holes in the sides of each end plate, and nuts for each of the through bolts.

2. The battery module manufacturing method according to claim 1, wherein in the alignment step, for each set of two battery cells adjacent to each other in the front and back, the two battery cells are arranged in opposite directions with their electrodes facing each other, the holding plate which is an intermediate plate is placed between the two battery cells, and for each set of two battery cells adjacent to each other in the front and back, the partition plate which is an intermediate plate is placed between the two battery cell sets.

3. A battery module manufacturing method according to claim 1 or 2, wherein at least one of the intermediate plates has a recess in the portion facing the battery cell, and further comprises a heater mounting step of mounting heaters to each of the recesses for suppressing a decrease in the temperature of the battery module.

4. A battery module manufacturing method according to any one of claims 1 to 3, comprising a charging step of charging each of the battery cells, wherein the pressing step is performed when each of the battery cells is charged and expanded.

5. A method for manufacturing a battery module, wherein a pressing device for a battery module is used in the pressing step, the method for manufacturing a battery module according to any one of claims 1 to 4, wherein the pressing device for a battery module comprises: a support portion that supports the front end plate from the front; a cylinder that pushes the rear end plate from the rear to the front; and a load cell that measures the force applied from the cylinder to the rear end plate as the pressing force.

6. A battery module comprising: a plurality of battery cells arranged in a line with one or more intermediate plates in between; two end plates sandwiching the plurality of battery cells from the front and rear; one or more through bolts passed through through holes in the sides of each intermediate plate and through holes in the sides of each end plate; and nuts used for each of the through bolts to fix the two end plates at intervals that press against the plurality of battery cells.

7. A pressing device for a battery module for pressing multiple battery cells of a battery module, wherein the battery module comprises: multiple battery cells arranged in a front-to-back line; and two end plates that sandwich the multiple battery cells from the front and back, and the pressing device for the battery module comprises: a support that supports the front end plate from the front; a cylinder that pushes the rear end plate from the rear to the front; and a load cell that measures the force applied from the cylinder to the rear end plate as a pressing force.

Images