Batteries and their manufacturing methods

Abstract

This invention provides a technology to suppress variations in discharge between multiple electrode sheets. [Solution] The battery comprises a plurality of electrode sheets stacked along a specific direction and connected in series, and an outer frame made of resin that covers the periphery of the plurality of electrode sheets, wherein a first hole is formed in the outer frame, extending from the surface of the outer frame in the specific direction, through at least one of the plurality of electrode sheets, and reaching a specific electrode sheet among the plurality of electrode sheets, and the side surface of the first hole extending in the specific direction is covered with resin.

Description

Technical Field

[0001] This specification relates to a battery in which a plurality of electrode sheets are stacked, and a method for manufacturing the battery.

Background Art

[0002] Patent Document 1 discloses a battery including a plurality of electrode sheets stacked along a specific direction and connected in series, and an outer frame made of resin that covers the peripheries of the plurality of electrode sheets.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to deactivate all of the plurality of electrode sheets, a method is assumed in which one end and the other end of the plurality of electrode sheets connected in series are short-circuited to discharge the plurality of electrode sheets collectively. However, in this method, variations in discharge occur between the plurality of electrode sheets, and there is a possibility that some of the electrode sheets cannot be sufficiently discharged.

[0005] This specification provides a technique for suppressing variations in discharge between a plurality of electrode sheets.

Means for Solving the Problems

[0006] A battery disclosed herein comprises a plurality of electrode sheets stacked in a particular direction and connected in series, and an outer frame made of resin covering the periphery of the plurality of electrode sheets, wherein a first hole is formed in the outer frame, extending from the surface of the outer frame in the particular direction, through at least one of the plurality of electrode sheets, to a particular electrode sheet among the plurality of electrode sheets, and the side surface of the first hole extending in the particular direction is covered with resin.

[0007] According to the above configuration, the first hole can be used to short-circuit one end of multiple electrode sheets with a specific electrode sheet. This allows the charge between that end and the specific electrode sheet to be discharged. Furthermore, the first hole can be used to short-circuit the other end of multiple electrode sheets with a specific electrode sheet. This allows the remaining charge between that other end and the first electrode sheet to be discharged. By using the first hole, the charges within multiple electrode sheets can be discharged separately. This suppresses variations in discharge between multiple electrode sheets compared to a method of discharging multiple electrode sheets simultaneously.

[0008] This specification further discloses a method for manufacturing a battery. The manufacturing method comprises the steps of: preparing one or more first electrode sheets, wherein a resin layer is formed in a frame shape on the periphery of the first electrode sheet, and through holes are formed that penetrate the resin layer and the first electrode sheet; preparing a second electrode sheet, wherein a resin layer is formed in a frame shape on the periphery of the second electrode sheet, and exposure holes are formed that pass through the resin layer to expose the second electrode sheet; and stacking a plurality of electrode sheets, including one or more of the first electrode sheets and the second electrode sheets, along a specific direction. The method comprises the steps of: forming a series of holes by aligning the through holes of the plurality of first electrode sheets and the exposed holes of the second electrode sheet along the specific direction; forming an outer frame covering the periphery of the plurality of electrode sheets by welding the resin layer of one or more of the first electrode sheets and the resin layer of the second electrode sheet, wherein a first hole is formed in the outer frame from the surface of the outer frame in the specific direction, penetrating one or more of the first electrode sheets and reaching the second electrode sheet; and covering the side surface of the first hole extending in the specific direction with resin.

[0009] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a battery. [Figure 2] This is a plan view of the electrode sheet. [Figure 3] This is an enlarged view of area III and a cross-sectional view thereof. [Figure 4] This is a diagram showing a method for manufacturing a battery. [Figure 5] This is a partial cross-sectional view of a battery in a vehicle state according to the first embodiment. [Figure 6] This is a partial cross-sectional view of a battery in a vehicle state according to the second embodiment. [Modes for carrying out the invention]

[0011] (First embodiment) (Battery configuration 2; Figure 1) Battery 2 comprises multiple electrode sheets 10A to 10C, multiple separators 20, and an outer frame 30. Figure 1 defines the XYZ coordinate system. As an example, battery 2 is a lithium-ion battery.

[0012] Multiple electrode sheets 10A to 10C are stacked along the Z-axis direction and connected in series. Electrode sheet 10A is a unipolar positive electrode sheet. Electrode sheet 10B is a bipolar electrode sheet. Electrode sheet 10C is a unipolar negative electrode sheet. Electrode sheet 10A is constructed by stacking a current collector 12 and a positive electrode active material 16. The current collector 12 of electrode sheet 10A may be, for example, aluminum foil. Electrode sheet 10B is constructed by stacking a negative electrode active material 14, a current collector 12, and a positive electrode active material 16. The current collector 12 of electrode sheet 10B may be, for example, a laminate of aluminum foil and copper foil. Electrode sheet 10C is constructed by stacking a negative electrode active material 14 and a current collector 12. The current collector 12 of electrode sheet 10C may be, for example, copper foil. Furthermore, in each electrode sheet 10A, 10B, and 10C, various positive electrode active materials and negative electrode active materials for lithium-ion batteries can be appropriately used for the positive electrode active material 16 and negative electrode active material 14.

[0013] A separator 20 is sandwiched between electrode sheet 10A and electrode sheet 10B. A separator 20 is also sandwiched between electrode sheet 10B and electrode sheet 10C. As shown in Figure 1, the electrode sheets 10A to 10C and the separator 20 are stacked alternately along the Z-axis. The outer frame 30 covers the periphery of the multiple electrode sheets 10A to 10C and is made of resin.

[0014] In addition, voltage detection terminals 40 for detecting the voltages of the electrode sheets 10A to 10C are connected to the electrode sheets 10A to 10C. The voltage detection terminals 40 extend from the peripheries of the electrode sheets 10A to 10C, penetrate the outer frame 30, and extend to the outside of the outer frame 30.

[0015] (Configuration of electrode sheet 10A; FIGS. 2 and 3) FIG. 2 shows a plan view of the electrode sheet 10A before lamination. A resin layer 50 is formed in a frame shape on the periphery of the electrode sheet 10A before lamination. The resin layer 50 covers both the front and back surfaces of the current collector 12 of the electrode sheet 10A. The resin layer 50 is a member that forms the basis of the outer frame 30 in FIG. 1. An exposed hole 100, a through hole 102, and a through hole 104 are formed in a part of the resin layer 50. As shown in FIG. 3, the exposed hole 100 passes through the resin layer 50 on the front side to expose the current collector 12 of the electrode sheet 10A. The through holes 102 and 104 penetrate the resin layer 50 on the front side, the current collector 12, and the resin layer 50 on the back side.

[0016] (Configuration of electrode sheet 10B; FIG. 3) A resin layer 50 similar to that of the electrode sheet 10A before lamination is also formed in a frame shape on the periphery of the electrode sheet 10B before lamination. Holes with a pattern different from that of the electrode sheet 10A are formed in the resin layer 50 of the electrode sheet 10B. Specifically, an exposed hole 112 for exposing the current collector 12 and a through hole 114 for penetrating the current collector 12 and the resin layer 50 are formed in a part of the resin layer 50 of the electrode sheet 10B.

[0017] (Configuration of electrode sheet 10C; FIG. 3) A resin layer 50 similar to those of the electrode sheets 10A and 10B before lamination is also formed in a frame shape on the periphery of the electrode sheet 10C before lamination. Holes with a pattern different from those of both the electrode sheets 10A and 10B are formed in the resin layer 50 of the electrode sheet 10C. Specifically, an exposed hole 124 for exposing the current collector 12 is formed in a part of the resin layer 50 of the electrode sheet 10C.

[0018] (Manufacturing method of battery 2; FIG. 4) Referring to FIG. 4, a method for manufacturing the battery 2 will be described. In the first step, electrode sheets 10A, 10B, and 10C before lamination are prepared. In the subsequent second step, the electrode sheets 10A, 10B, and 10C before lamination and the separator 20 are laminated alternately along the Z-axis direction. The separator 20 also has through holes (reference numerals omitted) formed along the Z-axis direction. In this step, the through hole 104 of the electrode sheet 10A, the through hole 114 of the electrode sheet 10B, the through hole of the separator 20, and the exposed hole 124 of the electrode sheet 10C are aligned along the Z-axis direction, thereby forming a series of holes 105. Also, the through hole 102 of the electrode sheet 10A, the through hole of the separator 20, and the exposed hole 112 of the electrode sheet 10B are aligned along the Z-axis direction, thereby forming a series of holes 103.

[0019] In the subsequent third step, the resin layers 50 of the respective electrode sheets 10A to 10C are welded to each other, thereby forming the outer frame 30. As a result, the series of holes 105 become holes 115 that reach the current collector 12 of the electrode sheet 10C through the electrode sheets 10A and 10B from the surface of the outer frame 30 in the Z-axis direction. Further, the series of holes 103 become holes 113 that reach the current collector 12 of the electrode sheet 10B through the electrode sheet 10A from the surface of the outer frame 30 in the Z-axis direction. Further, the exposed hole 100 becomes a hole 110 that exposes the current collector 12 of the electrode sheet 10A on the surface of the outer frame 30 in the Z-axis direction.

[0020] In the subsequent fourth step, the mold 200 is inserted into the three holes 110 to 115. The mold 200 includes a rod-shaped portion 210 inserted into the hole 110, a rod-shaped portion 213 inserted into the hole 113, and a rod-shaped portion 215 inserted into the hole 115. A gap through which resin flows is formed between each rod-shaped portion 210 to 215 and the side surface (hereinafter referred to as the "inner wall") extending along the Z-axis direction within each hole 110 to 115.

[0021] In the subsequent fifth step, resin is poured into the gap between the mold 200 and the three holes 110-115. This causes a resin wall 130 to be injection molded onto the inner wall of hole 110. Similarly, resin walls 133 and 135 are injection molded onto the inner walls of holes 113 and 115, respectively. By covering the inner walls of each hole 110-115 with resin walls 130-135, the gaps between each current collector 12 and the outer frame 30, and the gaps between each separator 20 and the outer frame 30 are sealed.

[0022] Once all processes are complete, battery 2 is finished. Battery 2 is installed in a vehicle such as an electric vehicle or a hybrid vehicle. When installed in a vehicle, the three holes 110-115 are closed with a cover 150, as shown in Figure 5.

[0023] For example, a situation may arise where battery 2 is removed from a vehicle for maintenance or dismantling. For safety reasons, it is desirable to deactivate all electrode sheets 10A to 10C of battery 2. For example, one possible method is to short-circuit electrode sheet 10A, which is one end of the stacked electrode sheets 10A to 10C, and electrode sheet 10C, which is the other end, to discharge electrode sheets 10A to 10C all at once. However, with this method, variations in discharge may occur among electrode sheets 10A to 10C, and some electrode sheets may not be able to discharge sufficiently.

[0024] The battery 2 in this embodiment has three holes 110 to 115. In this embodiment, the three holes 110 to 115 can be used to discharge each electrode sheet 10A to 10C separately. For example, a worker removes the cover 150 from the battery 2. The worker inserts lead wires that reach the current collector 12 into each of the holes 110 to 115. The worker short-circuits the lead wire inserted into hole 110 and the lead wire inserted into hole 113. This allows the charge accumulated on electrode sheets 10A and 10B to be discharged. The worker also short-circuits the lead wire inserted into hole 113 and the lead wire inserted into hole 115. This allows the charge accumulated on electrode sheets 10B and 10C to be discharged. This method suppresses variations in discharge between electrode sheets 10A to 10C compared to discharging electrode sheets 10A to 10C all at once.

[0025] It is also possible to discharge the electrode sheets 10A to 10C separately by short-circuiting the voltage detection terminals 40 together, for example, instead of using the three holes 110. However, the voltage detection terminals 40 are terminals for voltage detection and are relatively thin. Therefore, a large current cannot flow through them, and it takes a relatively long time for the discharge to be completed. Also, if the voltage detection terminals 40 are made thicker, it becomes necessary to add a sealing measure between the voltage detection terminals 40 and the outer frame 30. According to the configuration of this embodiment, relatively thick lead wires can be used according to the size of each hole 110 to 115. The time it takes for the discharge to be completed can be shortened relatively.

[0026] (Correspondence) Battery 2 and the Z-axis direction are examples of a "battery" and a "specific direction," respectively. Electrode sheets 10A to 10C and the outer frame 30 are examples of "multiple electrode sheets" and an "outer frame," respectively. Electrode sheet 10B and electrode sheet 10C are examples of a "specific electrode sheet" and another electrode sheet, respectively. Hole 113 and hole 115 are examples of a "first hole" and a second hole, respectively. Resin layer 50 is an example of a "resin layer." Electrode sheet 10A and through hole 102 are examples of a "first electrode sheet" and a "through hole," respectively. Electrode sheet 10B and exposed hole 112 are examples of a "second electrode sheet" and an "exposed hole," respectively. A series of holes 103 is an example of a "series of holes."

[0027] (Second example) This embodiment is the same as the first embodiment, except that the configuration of the lid 160 that closes the three holes 110 to 115 is different. The lid 160 is provided with three heat detection terminals 170, 173, and 175. A thermocouple is provided at one end of each of the three heat detection terminals 170, 173, and 175. Heat detection terminal 170 passes through hole 110, with one end in contact with the current collector 12 of electrode sheet 10A and the other end exposed from the lid 160. Heat detection terminal 173 passes through hole 113, with one end in contact with the current collector 12 of electrode sheet 10B and the other end exposed from the lid 160. Heat detection terminal 175 passes through hole 115, with one end in contact with the current collector 12 of electrode sheet 10C and the other end exposed from the lid 160. The other end of each heat detection terminal 170, 173, and 175 is connected to a circuit that detects the output value of a thermocouple in contact with the current collector 12. The temperatures of the electrode sheets 10A to 10C can be detected using the three heat detection terminals 170, 173, and 175. The temperatures of each heat detection terminal 170, 173, and 175 can be used, for example, to control the battery 2 mounted on the vehicle. The thermocouples provided at the other end of each heat detection terminal 170, 173, and 175 are examples of "thermocouples".

[0028] The following describes points to note regarding the technology shown in the examples. In each example, the number of holes 110 etc. formed in the outer frame 30 is not limited to 3, but may be 2, 4 or more. For example, only holes 113 may be formed in the outer frame 30. In this case, the charge accumulated in electrode sheets 10A and 10B can be discharged by short-circuiting the lead wire inserted into hole 113 with electrode sheet 10A, which is one end of the stacked electrode sheets 10A to 10C. Also, the charge accumulated in electrode sheets 10B and 10C can be discharged by short-circuiting the lead wire inserted into hole 113 with electrode sheet 10C, which is the other end of the stacked electrode sheets 10A to 10C. By forming at least one hole in the outer frame 30, each electrode sheet 10A to 10C can be discharged separately.

[0029] Furthermore, the number of stacked electrode sheets is not limited to three; it may be four or more. Battery 2 may be equipped with two or more bipolar electrode sheets. [Explanation of Symbols]

[0030] 2: Battery, 10A~10C: Electrode sheet, 12: Current collector, 14: Negative electrode active material, 16: Positive electrode active material, 20: Separator, 30: Outer frame, 40: Voltage detection terminal, 50: Resin layer, 100: Exposed hole, 102: Through hole, 104: Through hole, 112: Exposed hole, 114: Through hole, 124: Exposed hole, 103, 105: Series of holes, 110, 113, 115: Holes, 130, 133, 135: Resin wall, 150, 160: Cover, 170, 173, 175: Heat detection terminal, 200: Mold, 210, 213, 215: Rod-shaped part

Claims

1. Multiple electrode sheets are stacked along a specific direction and connected in series, The outer frame, made of resin, covers the periphery of the plurality of electrode sheets, Equipped with, The outer frame has a first hole formed therein that penetrates at least one of the plurality of electrode sheets from the surface of the outer frame in the particular direction and reaches a specific electrode sheet among the plurality of electrode sheets. The side surface of the first hole extending in the particular direction is covered with resin. battery.

2. The outer frame has a plurality of holes formed therein, including the first hole and the second hole. The battery according to claim 1, wherein the second hole extends from the surface to an electrode sheet among the plurality of electrode sheets that is different from the specific electrode sheet.

3. The battery according to claim 1, further comprising a thermocouple inserted into the first hole and in contact with the periphery of the specific electrode sheet.

4. The battery according to any one of claims 1 to 3, wherein the plurality of electrode sheets include at least one bipolar electrode sheet.

5. A method for manufacturing a battery, A step of preparing one or more first electrode sheets, wherein a resin layer is formed in a frame shape around the periphery of the first electrode sheet, and through holes are formed that penetrate the resin layer and the first electrode sheet. A step of preparing a second electrode sheet, wherein a resin layer is formed in a frame shape around the periphery of the second electrode sheet, and an exposure hole is formed that allows the resin layer to pass through and expose the second electrode sheet. A step of stacking and arranging a plurality of electrode sheets, including one or more first electrode sheets and a second electrode sheet, along a specific direction, wherein the through holes of one or more first electrode sheets and the exposed holes of the second electrode sheet are aligned along the specific direction to form a series of holes. A step of forming an outer frame covering the periphery of the plurality of electrode sheets by welding the resin layer of one or more of the first electrode sheets and the resin layer of the second electrode sheet, wherein a first hole is formed in the outer frame, extending from the surface of the outer frame in the specific direction, through one or more of the first electrode sheets, and reaching the second electrode sheet. A step of covering the side surface of the first hole extending in the specific direction with resin, A manufacturing method that includes the following features.

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