Battery module

Abstract

A battery module includes a battery element, a first current collector electrically connected to the battery element, a second current collector disposed so as to face the first current collector and electrically connected to the first current collector, and a plurality of resin insulators disposed between the first current collector and the second current collector. The battery element is provided with a positive electrode, a negative electrode, and a resin separator disposed between the positive electrode and the negative electrode, the first current collector and the second current collector are electrically insulated by the insulator at a portion where the insulator is disposed therebetween, and are electrically connected at a portion where the insulator is not disposed therebetween, and the melting point of the resin of the insulator is lower than the melting point of the resin of the separator. The insulator melts and expands between the first current collector and the second current collector by heat generated by energization of the first current collector and the second current collector.

Description

Technical Field

[0001] The technology disclosed in this specification relates to battery modules. Background Technology

[0002] A battery module is disclosed in Japanese Patent Application Publication No. 2007-66806. The battery module of Japanese Patent Application Publication No. 2007-66806 includes a first current collector, a second current collector electrically connected to the first current collector, multiple insulators disposed between the first and second current collectors, and a battery element electrically connected to the first current collector. The portions of the first and second current collectors with insulators disposed between them are electrically insulated by the insulators, while the portions without insulators are electrically connected. Summary of the Invention

[0003] In battery modules, excessive current may flow due to external short circuits, causing the battery module to overheat abnormally and potentially damaging battery components. Therefore, this specification provides a technique to suppress abnormal temperature rise in battery modules.

[0004] In a first aspect of this technology, a battery module includes: a battery element; a first current collector electrically connected to the battery element; a second current collector disposed opposite to and electrically connected to the first current collector; and a plurality of resin insulators disposed between the first and second current collectors. The battery element includes a positive electrode, a negative electrode, and a resin spacer disposed between the positive and negative electrodes. The portions of the first and second current collectors with the insulator disposed therebetween are electrically insulated by the insulator, while the portions without the insulator are electrically connected. The melting point of the resin of the insulator is lower than the melting point of the resin of the spacer. The insulator melts due to heat generated by energizing the first and second current collectors and expands between the first and second current collectors.

[0005] According to this structure, when the first and second current collectors overheat abnormally due to excessive current flowing through the battery module, the insulator melts and expands between the first and second current collectors. This allows for the interruption or suppression of current flow between the first and second current collectors. Consequently, excessive current flowing through the battery module can be suppressed, and abnormal temperature rise in the battery module can be prevented. Furthermore, by melting the insulator before the spacer melts, the battery components can be protected.

[0006] In the second embodiment, it is also possible that, in the first embodiment described above, the thickness of the insulator is thinner than the thickness of the first current collector and thinner than the thickness of the second current collector.

[0007] In the third approach, it is also possible that, in the first or second approach described above, a plurality of the insulators are arranged in a first direction and extend in a second direction different from the first direction.

[0008] In the fourth embodiment, it is also possible that, in the third embodiment described above, the width of the insulator in the first direction is narrower than the width between adjacent insulators in the first direction.

[0009] In the fifth method, or in any of the methods 1 to 4 above, the melting point of the resin of the insulator is higher than the upper limit of the temperature during normal use of the battery module. Attached Figure Description

[0010] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein the same symbols denote the same elements.

[0011] Figure 1 This is a diagram schematically illustrating a battery module of an embodiment.

[0012] Figure 2 yes Figure 1 Sectional view II-II;

[0013] Figure 3 This is a diagram schematically illustrating a battery module of an embodiment. Detailed Implementation

[0014] The battery module 2 of the embodiment will be described with reference to the accompanying drawings. Figure 1 As shown, the battery module 2 of this embodiment includes a plurality of battery elements 10 and an outer casing 30 that houses the plurality of battery elements 10. Furthermore, the battery module 2 includes a first positive current collector 20 and a first negative current collector 22 in each of the plurality of battery elements 10 for collecting electricity generated by the battery elements 10. Additionally, the battery module 2 includes a second positive current collector 50 and a second negative current collector 52 for collecting electricity generated by the plurality of battery elements 10. Moreover, the battery module 2 includes a plurality of positive insulators 40 disposed between the first positive current collector 20 and the second positive current collector 50, and a plurality of negative insulators 42 disposed between the first negative current collector 22 and the second negative current collector 52.

[0015] Multiple battery elements 10 are arranged in an overlapping manner inside the casing 30 and electrically connected in series. Each battery element 10, for example, constitutes a lithium-ion battery. Each battery element 10 has a positive electrode 12, a negative electrode 14, and a spacer 16 disposed between the positive electrode 12 and the negative electrode 14. In addition, each battery element 10 has an electrolyte 18.

[0016] Multiple battery elements 10 are arranged such that the positive electrode 12 of one adjacent battery element 10 faces the negative electrode 14 of another adjacent battery element 10. The multiple battery elements 10 have their respective positive electrodes 12 facing one side. Figure 1 (The middle is at the top), and each of their negative electrodes 14 faces the other side ( Figure 1 Configured in the manner shown below.

[0017] The positive electrode 12 of battery element 10 is disposed on the surface of the first positive current collector 20. The positive electrode 12 is coated on the surface of the first positive current collector 20. The positive electrode 12 is manufactured, for example, by coating a paste containing a positive electrode active material onto the surface of the first positive current collector 20 and then drying it. The positive electrode active material used as the material of the positive electrode 12 is, for example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium nickel oxide (LiNiO2), etc., and is not particularly limited. In addition, the manufacturing method of the positive electrode 12 is not particularly limited.

[0018] The negative electrode 14 of battery element 10 is disposed on the surface of the first negative electrode current collector 22. The negative electrode 14 is coated on the surface of the first negative electrode current collector 22. The negative electrode 14 is manufactured, for example, by coating a paste containing a negative electrode active material onto the surface of the first negative electrode current collector 22 and then drying it. The negative electrode active material used as the material of the negative electrode 14 is, for example, graphite, hard carbon, soft carbon, etc., but is not particularly limited. In addition, the manufacturing method of the negative electrode 14 is not particularly limited.

[0019] The spacer 16 is made of an ion-conductive resin in the form of a film. The spacer 16 is made of, for example, polypropylene (PP), polyethylene (PE), or a combination thereof. The thickness of the spacer 16 is, for example, 20 μm. The periphery of the spacer 16 is fixed to a support 32 disposed inside the outer casing 30.

[0020] Electrolyte 18 is filled between the positive electrode 12 and the spacer 16, and between the negative electrode 14 and the spacer 16, in battery element 10. Electrolyte 18 is a liquid containing an electrolyte. The electrolyte is, for example, a lithium salt such as LiPF6, LiClO4, or LiBF4, but is not particularly limited.

[0021] The first positive current collector 20 is made of a conductive metal. For example, it is made of a foil containing aluminum (Al). The thickness of the first positive current collector 20 is, for example, 100 μm or less. The first positive current collector 20 is electrically connected to the battery element 10 and collects the electricity generated by the battery element 10. The first positive current collector 20 is also electrically connected to the positive electrode 12 of the battery element 10 and collects electricity from the positive electrode 12. The periphery of the first positive current collector 20 is fixed to a support 32 disposed inside the outer casing 30.

[0022] The first negative electrode current collector 22 is made of a conductive metal. For example, it is made of a foil containing copper (Cu). The thickness of the first negative electrode current collector 22 is, for example, 100 μm or less. The first negative electrode current collector 22 is electrically connected to the battery element 10 and collects the electricity generated by the battery element 10. The first negative electrode current collector 22 is also electrically connected to the negative electrode 14 of the battery element 10 and collects electricity from the negative electrode 14. The periphery of the first negative electrode current collector 22 is fixed to a support 32 disposed inside the outer casing 30.

[0023] The opposing positive first current collectors 20 and negative first current collectors 22 are integrated by bonding. The opposing positive first current collectors 20 and negative first current collectors 22 are electrically connected. The opposing positive first current collectors 20 and negative first current collectors 22 can also be prefabricated as a single unit.

[0024] The second positive current collector 50 is made of a conductive metal. For example, it is made of a foil containing aluminum (Al). The thickness of the second positive current collector 50 is, for example, 100 μm or less. The second positive current collector 50 is electrically connected to the battery element 10 via the first positive current collector 20, and collects the electricity generated by the battery element 10. The second positive current collector 50 is the outermost of the plurality of first positive current collectors 20 (located in...). Figure 1 The positive first current collector 20 (located on the top side) is electrically connected, and current is collected from the positive first current collector 20. The periphery of the positive second current collector 50 is fixed to the outer casing 30.

[0025] The second negative electrode current collector 52 is made of a conductive metal. For example, it is made of a foil containing copper (Cu). The thickness of the second negative electrode current collector 52 is, for example, 100 μm or less. The second negative electrode current collector 52 is electrically connected to the battery element 10 via the first negative electrode current collector 22, and collects the electricity generated by the battery element 10. The second negative electrode current collector 52 is the outermost of the plurality of first negative electrode current collectors 22 (located in...). Figure 1 The negative electrode first current collector 22 (located on the lower side) is electrically connected, and current is collected from the negative electrode first current collector 22. The periphery of the negative electrode second current collector 52 is fixed to the outer casing 30.

[0026] A support 32 disposed inside the outer casing 30 supports the positive first current collector 20, the negative first current collector 22, and the spacer 16. The support 32 seals the portion of the battery element 10 filled with electrolyte 18. Specifically, the support 32 seals the spacer 16 between the positive first current collector 20 and the spacer 16, and between the negative first current collector 22 and the spacer 16. The support 32 is made of an insulating resin. For example, the support 32 is made of polypropylene (PP), polyethylene (PE), or a combination thereof.

[0027] The outer casing 30 houses the battery element 10 and the support 32 that supports the battery element 10. The outer casing 30 surrounds the battery element 10 and the support 32. The outer casing 30 is made of an insulating resin. The outer casing 30 is made of, for example, polypropylene (PP), polyethylene (PE), or a combination thereof.

[0028] The outer casing 30 has a positive electrode side opening 33a that opens on the positive electrode side of the battery element 10 and a negative electrode side opening 33b that opens on the negative electrode side of the battery element 10. A second positive electrode current collector 50 is disposed in the positive electrode side opening 33a. The second positive electrode current collector 50 closes the positive electrode side opening 33a. The periphery of the second positive electrode current collector 50 is fixed to the outer casing 30. Similarly, a second negative electrode current collector 52 is disposed in the negative electrode side opening 33b. The second negative electrode current collector 52 closes the negative electrode side opening 33b. The periphery of the second negative electrode current collector 52 is fixed to the outer casing 30.

[0029] Next, the plurality of positive electrode insulators 40 disposed between the first positive electrode current collector 20 and the second positive electrode current collector 50 will be described. The plurality of positive electrode insulators 40 extend along the surface of the first positive electrode current collector 20 (… Figure 1 The middle is the upper surface) and along the surface of the second current collector 50 of the positive electrode ( Figure 1 (The middle is the lower surface) is set.

[0030] The first positive current collector 20 and the second positive current collector 50 are in close contact with a plurality of positive insulators 40 sandwiched between them. The first positive current collector 20 and the second positive current collector 50 are in close contact with a plurality of positive insulators 40 between them during the vacuum forming of the outer casing 30. The first positive current collector 20 and the second positive current collector 50 are separated by the positive insulators 40 in the portions where they are located, and are in contact in the portions where they are not located. The first positive current collector 20 and the second positive current collector 50 are electrically insulated from the positive insulators 40 in the portions where they are located, and are electrically connected in the portions where they are not located.

[0031] like Figure 2 As shown, multiple positive electrode insulators 40 are arranged in a striped pattern. The multiple positive electrode insulators 40 are in the first direction ( Figure 2 The positive electrode insulators 40 are arranged at intervals in a second direction (orthogonal to the first direction). Figure 2 It extends in the Y direction. The width W1 of each positive insulator 40 in the first direction is narrower than the width W2 between adjacent positive insulators 40 in the first direction. For example, W1 ≤ 0.3W2.

[0032] Each positive electrode insulator 40 is formed into a film. The thickness of the positive electrode insulator 40 is, for example, 20 μm. The thickness of the positive electrode insulator 40 is thinner than the thickness of the first positive electrode current collector 20 and thinner than the thickness of the second positive electrode current collector 50. The thickness of the positive electrode insulator 40 is, for example, less than 20% of the thickness of the first positive electrode current collector 20. The thickness of the positive electrode insulator 40 is, for example, less than 20% of the thickness of the second positive electrode current collector 50.

[0033] Each positive electrode insulator 40 is made of resin. The positive electrode insulator 40 is made, for example, of low-density polyethylene (PE), high-density polyethylene (PE), polypropylene (PP), or a combination of several of these resins. The melting point of low-density polyethylene (PE) is approximately 100°C to 115°C. The melting point of high-density polyethylene (PE) is approximately 125°C to 140°C. The melting point of polypropylene (PP) is approximately 160°C. The melting point of the resin in the positive electrode insulator 40 is lower than the melting point of the resin in the spacer 16 of the battery element 10. For example, the melting point of the resin in the positive electrode insulator 40 is at least 20°C lower than the melting point of the resin in the spacer 16 of the battery element 10.

[0034] Furthermore, the melting point of the resin in the positive electrode insulator 40 can be, for example, a temperature higher than the upper limit of the normal operating temperature of the battery module 2. For example, the melting point of the resin in the positive electrode insulator 40 may be at least 20°C higher than the upper limit of the normal operating temperature of the battery module 2. The normal operating temperature of the battery module 2 can also be, for example, a temperature managed by the cooling system (not shown) of the battery module 2, taking into account the lifespan and safety of the battery module 2. The upper limit of the normal operating temperature of the battery module 2 may be, for example, 70°C.

[0035] Furthermore, the melting point of the resin in the positive electrode insulator 40 can be, for example, a temperature lower than the overheating mode occurrence temperature. For example, the melting point of the resin in the positive electrode insulator 40 is a temperature at least 40°C lower than the overheating mode occurrence temperature. The overheating mode occurrence temperature can, for example, be set to the same temperature as the melting point of the resin in the spacer 16 of the battery element 10.

[0036] The structure of the plurality of negative electrode insulators 42 disposed between the first negative electrode current collector 22 and the second negative electrode current collector 52 is the same as the structure of the plurality of positive electrode insulators 40 disposed between the first positive electrode current collector 20 and the second positive electrode current collector 50, therefore detailed description is omitted. The configuration of the negative electrode insulators 42 will be explained by replacing "positive electrode" with "negative electrode" in the above-mentioned positive electrode insulators 40.

[0037] In the battery module 2 described above, when current flows through the first positive current collector 20 and the second positive current collector 50 due to power generation by the multiple battery elements 10, the first positive current collector 20 and the second positive current collector 50 generate heat due to the energization. In the battery module 2, when the first positive current collector 20 and the second positive current collector 50 generate heat, the temperature of the multiple positive insulators 40 disposed between the first positive current collector 20 and the second positive current collector 50 increases. Each positive insulator 40 melts when its temperature reaches a temperature above its melting point.

[0038] like Figure 3 As shown, multiple positive insulators 40 disposed between the first positive current collector 20 and the second positive current collector 50 are laterally extended between them by melting. This expands the area of ​​insulation between the first positive current collector 20 and the second positive current collector 50 by the multiple positive insulators 40. Consequently, the resistance between the first positive current collector 20 and the second positive current collector 50 increases. As a result, the current flowing through the first positive current collector 20 and the second positive current collector 50 decreases, or the current is interrupted.

[0039] The above description focuses on the positive electrode side of battery module 2, but the negative electrode side is the same. Regarding the negative electrode side, the description will be provided by replacing "positive electrode" with "negative electrode" in the above description.

[0040] Effect

[0041] The battery module 2 of the embodiment has been described above. As can be seen from the above description, the battery module 2 includes: a first positive current collector 20, which is electrically connected to the battery element 10; and a second positive current collector 50, which is arranged opposite to and electrically connected to the first positive current collector 20. Furthermore, the battery module 2 includes a plurality of resin positive electrode insulators 40 disposed between the first positive current collector 20 and the second positive current collector 50. The battery element 10 includes a positive electrode 12, a negative electrode 14, and a resin spacer 16 disposed between the positive electrode 12 and the negative electrode 14. The melting point of the resin in the positive electrode insulator 40 is lower than the melting point of the resin in the spacer 16. The positive electrode insulator 40 melts due to the heat generated by the current flowing through the first positive current collector 20 and the second positive current collector 50, and expands between the first positive current collector 20 and the second positive current collector 50.

[0042] According to this structure, when the first positive current collector 20 and the second positive current collector 50 abnormally heat up due to excessive current flowing through the battery module 2, the positive electrode insulator 40 melts and expands between the first positive current collector 20 and the second positive current collector 50. This cuts off or suppresses the current flow between the first positive current collector 20 and the second positive current collector 50. As a result, excessive current flowing through the battery module 2 can be suppressed, and abnormal temperature rise in the battery module 2 can be prevented. Furthermore, by melting the positive electrode insulator 40 before the spacer 16 melts, the battery element 10 can be protected.

[0043] The thickness of the positive electrode insulator 40 is thinner than the thickness of the first positive electrode current collector 20 and also thinner than the thickness of the second positive electrode current collector 50. This structure allows for good contact between the first positive electrode current collector 20 and the second positive electrode current collector 50 under normal conditions. Furthermore, it allows for a reduction in the overall thickness of the battery module 2.

[0044] Multiple positive insulators 40 in the first direction ( Figure 2 Arranged in the X direction, in a second direction different from the first direction ( Figure 2 It extends in the Y direction. Based on this configuration, multiple positive electrode insulators 40 can be easily manufactured.

[0045] The width W1 of the positive electrode insulator 40 in the first direction is narrower than the width W2 between adjacent positive electrode insulators 40 in the first direction. According to this structure, the first positive electrode current collector 20 and the second positive electrode current collector 50 can be in good contact under normal circumstances.

[0046] Furthermore, while the positive electrode side of battery module 2 was described above, the negative electrode side is the same as the positive electrode side. Regarding the negative electrode side, the description will be provided by replacing "positive electrode" with "negative electrode" in the above description.

[0047] Variations

[0048] (1) In the above embodiments, the plurality of positive electrode insulators 40 are arranged in a striped pattern, but the arrangement is not particularly limited. The plurality of positive electrode insulators 40 can be arranged at intervals. The plurality of negative electrode insulators 42 are arranged in the same way.

[0049] (2) In the above embodiment, the direction in which the plurality of positive electrode insulators 40 are arranged (first direction) is orthogonal to the direction in which each positive electrode insulator 40 extends (second direction), but this configuration is not limited. The first direction and the second direction may also not be orthogonal.

[0050] (3) The difference between the melting point of the resin of the positive electrode insulator 40 and the melting point of the spacer 16 of the battery element 10 can be greater than the difference between the melting point of the resin of the positive electrode insulator 40 and the upper limit of the normal operating temperature of the battery module 2. According to this structure, abnormal temperature rise of the battery module 2 can be further suppressed.

[0051] The specific examples of the present invention have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes technologies obtained by various modifications and alterations to the specific examples described above. The technical elements illustrated in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

Claims

1. A battery module, comprising: Battery elements; The first current collector is electrically connected to the battery element; The second collector is configured opposite to the first collector and is electrically connected to the first collector; and Multiple resin insulators are disposed between the first current collector and the second current collector. The battery features include: positive electrode; Negative electrode; and A resin spacer disposed between the positive electrode and the negative electrode. The portions of the first current collector and the second current collector that are provided with the insulator between them are electrically insulated by the insulator, while the portions that are not provided with the insulator between them are electrically connected. The melting point of the resin in the insulator is lower than that of the resin in the spacer. The insulator melts due to the heat generated by the energization of the first and second collectors and expands between the first and second collectors.

2. The battery module according to claim 1, The thickness of the insulator is thinner than the thickness of the first collector and thinner than the thickness of the second collector.

3. The battery module according to claim 1 or 2, The plurality of said insulators are arranged in a first direction and extend in a second direction different from the first direction.

4. The battery module according to claim 3, The width of the insulator in the first direction is narrower than the width between adjacent insulators in the first direction.

5. The battery module according to claim 1 or 2, The resin of the insulator has a melting point higher than the upper limit of the temperature range during normal use of the battery module.

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