How to disassemble a battery pack

Abstract

To remove metal components from the case without requiring complicated procedures when disassembling a battery pack. [Solution] A method for disassembling a battery pack in which a battery and a cooler for cooling the battery are housed inside a case, and the battery is bonded to the case with adhesive, the method comprising a disassembly step of removing the battery fixed to the case with adhesive from the case, wherein the cooler has a flow path through which a refrigerant for cooling the battery flows, and the disassembly step comprises a cooling step of flowing a different refrigerant through the flow path than that used when the battery is in use to bring the cooler to a lower temperature than when the battery is in use.

Description

Technical Field

[0001] The present invention relates to a method for disassembling a battery pack.

Background Art

[0002] Patent Document 1 discloses a method for disassembling a battery pack having a structure for passing a wire saw between a metal part adhered to a case and the case, including a step of cutting an adhesive with the wire saw when removing the metal part from the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the disassembly method using a wire saw as described in Patent Document 1, when the battery is large or the adhesion range by the adhesive is wide, the number of locations where the adhesive needs to be cut increases, and the disassembly work becomes laborious. In addition, in the cutting of the adhesive, smoke is generated by bringing the heated blade into contact with the adhesive.

[0005] <s The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for disassembling a battery pack that can remove a metal part from a case without requiring complicated work when disassembling the battery pack.

Means for Solving the Problems

[0006] The present invention relates to a method for disassembling a battery pack in which a battery and a cooler for cooling the battery are housed inside a case, and the battery is bonded to the case with an adhesive, the method comprising a disassembly step of removing the battery, which is fixed to the case with the adhesive, from the case, wherein the cooler has a passage through which a refrigerant for cooling the battery flows, and the disassembly step comprises a cooling step of flowing a different refrigerant through the passage than that used when the battery is in use to bring the cooler to a lower temperature than when the battery is in use. [Effects of the Invention]

[0007] In this invention, metal components can be removed from the case without requiring complicated procedures when disassembling the battery pack. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the battery pack in the embodiment. [Figure 2] This is a cross-sectional view showing section AA in Figure 1. [Modes for carrying out the invention]

[0009] The following describes in detail the method for disassembling the battery pack in the embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0010] Figure 1 is a schematic diagram showing a battery pack in an embodiment. Figure 2 is a cross-sectional view showing section AA of Figure 1. The battery pack 1 comprises a battery 2, a case 3, a cooler 4, a control device 5, an adhesive 6, and refrigerant pipes 7 and 8.

[0011] The battery pack 1 has a stack 10 in which multiple batteries 2 are stacked. The batteries 2 are formed in a rectangular shape in plan view. The batteries 2 are energy storage modules containing multiple battery cells. The battery pack 1 comprises multiple energy storage modules. The batteries 2 are composed of lithium-ion batteries. For example, the batteries 2 are bipolar lithium-ion batteries having bipolar electrodes. Adjacent batteries 2 in the stacking direction of the stack 10 are electrically connected to each other. Multiple batteries 2 in the stack 10 are electrically connected in series.

[0012] Case 3 is a battery pack case that houses multiple energy storage modules. Case 3 includes a metal lower case. Case 3 houses batteries 2, coolers 4, and control equipment 5. Coolers 4 are coolers that cool batteries 2. Control equipment 5 is control equipment that controls batteries 2. Multiple batteries 2 and multiple coolers 4 are housed inside Case 3. Case 3 has a first housing chamber that houses batteries 2 and coolers 4, and a second housing chamber that houses control equipment 5. The first housing chamber and the second housing chamber are separated by a partition wall 31. The first housing chamber is located in the center of Case 3. The second housing chamber is located in front of the first housing chamber. The inside of the first housing chamber is filled with adhesive 6.

[0013] As shown in Figure 2, inside case 3, coolers 4 are placed between adjacent batteries 2 in the stacking direction. In the stacked structure 10, the batteries 2 and coolers 4 are stacked alternately in the height direction of case 3. The stacking direction of the stacked structure 10 and the height direction of case 3 are the same direction.

[0014] In battery pack 1, the battery 2 is bonded to the case 3 by adhesive 6. Adhesive 6 is made of resin. The inside of case 3 is filled with adhesive 6 so that the battery 2 and the cooler 4 are embedded. The cooler 4 is bonded to the battery 2 by adhesive 6. Adhesive 6 is interposed between the battery 2 and the cooler 4. In battery pack 1, adhesive 6 is bonded to the entire surface of the battery 2. The battery 2 is fixed to case 3 by adhesive 6.

[0015] The cooler 4 is formed in a flat plate shape that extends in the length and width directions of the case 3. The cooler 4 is made of metal. Inside the cooler 4, there is a flow path through which a refrigerant for cooling the battery 2 flows. The cooler 4 is connected to refrigerant pipes 7 and 8. Refrigerant pipe 7 is a supply pipe that supplies refrigerant to the cooler 4 from outside the case 3. Refrigerant pipe 8 is a discharge pipe that discharges the refrigerant that has flowed through the cooler 4 to the outside of the case 3. Refrigerant pipes 7 and 8 extend from the front side of the case 3, through the second housing chamber, to the inside of the first housing chamber. For the multiple coolers 4 housed in the first housing chamber, the flow path of each cooler 4 is in communication with refrigerant pipes 7 and 8. When the battery 2 is used in the battery pack 1 (when the battery is in use), refrigerant for cooling the battery 2 is supplied from refrigerant pipe 7 to the cooler 4, and that refrigerant flows through the flow path inside the cooler 4.

[0016] In the battery pack 1 configured in this way, it will be disassembled during recycling, and it is desirable that the disassembly be easy. Conventional methods of cutting adhesive are time-consuming and involve dust, smoke, and damage. Therefore, in the disassembly method of the battery pack 1 in this embodiment, the adhesive strength of the adhesive 6 is eliminated so that the battery pack 1 can be disassembled.

[0017] The method for disassembling the battery pack 1 includes a disassembly step of removing the battery 2, which is bonded to the case 3 with adhesive 6, from the case 3. The disassembly step includes a cooling step of circulating a different refrigerant than that used when the battery is in use through the flow path of the cooler 4 to lower the temperature of the cooler 4 to a temperature lower than that used when the battery is in use. A temperature lower than that used when the battery is in use means a temperature lower than the design lower limit of the battery pack 1. The cooling step lowers the temperature of the cooler 4 to a temperature lower than that used when the battery is in use, cooling the battery pack 1 itself and partially cooling the inside of the case 3. In the cooling step, for example, the cooler 4 is cooled to -100°C. In this way, the cooling step cools the cooler 4 to a temperature lower than that used when the battery is in use by circulating a different refrigerant than that used when the battery is in use.

[0018] The cooling process includes a step (peeling step) of peeling the metal component and the adhesive 6 due to the difference in the linear expansion coefficients between the metal component and the adhesive 6. The battery 2, the case 3, and the cooler 4 are all metal components. In the peeling step, due to the difference in the linear expansion coefficients between the battery 2 and the adhesive 6 in the state where the cooler 4 is cooled to -100°C by the cooling process, the adhesive fixing surface 2a of the battery 2 and the adhesive 6 are peeled at the interface. Similarly, in the peeling step, due to the difference in the linear expansion coefficients between the case 3 and the adhesive 6 in the state where the cooler 4 is cooled to -100°C by the cooling process, the adhesive fixing surface 3a of the case 3 and the adhesive 6 are peeled at the interface. Further, in the peeling step, due to the difference in the linear expansion coefficients between the cooler 4 and the adhesive 6 in the state where the cooler 4 is cooled to -100°C by the cooling process, the adhesive fixing surface 4a of the cooler 4 and the adhesive 6 are peeled at the interface.

[0019] In addition, the cooling process includes a step of cracking the adhesive 6 due to the difference in the linear expansion coefficients between the metal component and the adhesive 6 in the state where the cooler 4 is cooled to -100°C. This cracking step can be performed simultaneously with the peeling step. In the cooling process, due to the difference in the linear expansion coefficients between the metal component and the adhesive 6, interface peeling and cracking of the adhesive 6 are performed.

[0020] As described above, according to the embodiment, by cooling the battery pack 1 itself in the cooling process, the adhesive force of the adhesive 6 can be eliminated, and the battery pack 1 can be disassembled without the need for laborious operations such as cutting the adhesive, and operations involving dust generation, smoke generation, and destruction. Thereby, when disassembling the battery pack 1, the metal component can be easily taken out from the case 3.

[0021] Note that the battery pack 1 is not limited to a structure in which the battery 2 is adhered over the entire surface. A structure in which the adhesive 6 is adhered to a part of the surface of the battery 2 may be used. The battery pack 1 may have any structure as long as the battery 2 to be peeled off is cooled by the cooler 4.

[0022] Also, the temperature of the cooler 4 cooled in the cooling process is not limited to -100°C. In the cooling process, a refrigerant capable of lowering the temperature of the cooler 4 to a low temperature range where the adhesive 6 can be embrittled may be circulated through the flow path of the cooler 4.

[0023] In addition, in the battery pack 1, a resin coating may be applied to the surface of the metal parts. The structure is not limited to the one in which the metal parts and the adhesive 6 are directly adhered, and a structure in which the metal parts and the adhesive 6 are adhered via a resin coating may also be acceptable.

Explanation of Reference Numerals

[0024] 1 Battery pack 2 Battery 3 Case 4 Cooler 5 Control device 6 Adhesive 7, 8 Refrigerant pipes

Claims

1. A method for disassembling a battery pack in which a battery and a cooler for cooling the battery are housed inside a case, and the battery is bonded to the case with an adhesive, The disassembly step includes removing the battery, which is fixed to the case with the adhesive, from the case. The cooler has a flow path through which a refrigerant for cooling the battery flows, The disassembly step includes a cooling step in which a different refrigerant than that used when the battery is in use is circulated through the flow path to bring the cooler to a lower temperature than when the battery is in use. A method for disassembling a battery pack, characterized by the following features.

2. The cooler is attached to the battery by the adhesive, The battery, the cooler, and the case are all metal parts. The aforementioned adhesive is composed of resin, The cooling step includes a step of causing interfacial delamination between the metal part and the adhesive due to the difference in the coefficient of linear expansion between the metal part and the adhesive. The method for disassembling a battery pack as described in feature 1.

3. The inside of the case is filled with adhesive so that the battery and the cooler are embedded within it. The cooling step includes a step of causing the adhesive to crack due to the difference in the coefficient of linear expansion between the metal part and the adhesive. The method for disassembling a battery pack as described in feature 2.

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