Secondary batteries
The secondary battery design improves heat dissipation through a thermally conductive resin heat transfer member, addressing the challenge of maintaining energy density and cost efficiency by forming an efficient heat dissipation path without additional components.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- NISSAN MOTOR CO LTD
- Filing Date
- 2022-06-22
- Publication Date
- 2026-06-26
AI Technical Summary
Existing secondary battery designs face challenges in improving heat dissipation performance without compromising energy density and increasing costs due to the addition of additional heat transfer components.
A secondary battery design incorporating a thermally conductive resin heat transfer member bonded to the current collector and outer casing, forming a heat dissipation path from the power generation element to the outside, while minimizing additional components to maintain energy density and cost.
Enhances heat dissipation performance by increasing the heat dissipation path without enlarging the battery size or increasing component count, thus maintaining energy density and cost efficiency.
Smart Images
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Abstract
Description
[Technical Field]
[0001] This invention relates to a secondary battery. [Background technology]
[0002] Patent Document 1 discloses a battery cell in which an electrode stack is enclosed in an outer casing material, and which has a configuration for improving the cooling efficiency of the all-solid-state battery cell, in which a first heat transfer material is arranged inside the outer casing material so as to be in contact with the electrode stack and the outer casing material. [Prior art documents] [Patent Documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2020-113496 [Overview of the Initiative] [Problems that the invention aims to solve]
[0004] In the battery cell described in the above-mentioned document, heat generated in the electrode stack is transferred to the first heat transfer material. However, in order to improve the heat dissipation performance of the secondary battery, it is necessary to further transfer the heat from the first heat transfer material to the outside. In this regard, the above-mentioned document forms a heat transfer path by creating a battery module in which an external first heat transfer material, a lower plate, an external second heat transfer material, and a coolant are sequentially arranged at the bottom of the battery cell.
[0005] In other words, the battery cells described in the above-mentioned literature alone are not sufficient to improve heat dissipation performance. Furthermore, if components such as the first external heat transfer material are added to the battery module to improve heat dissipation performance, it will result in a decrease in energy density due to the larger size compared to a single battery cell, and an increase in cost due to the increase in the number of components.
[0006] Therefore, the present invention aims to provide a secondary battery that can improve heat dissipation performance while suppressing a decrease in energy density and an increase in cost. [Means for solving the problem]
[0007] According to one aspect of the present invention, a secondary battery is provided comprising: a power generation element comprising a positive electrode having a positive electrode active material layer formed on at least one surface of a flat positive electrode current collector and a negative electrode having a negative electrode active material layer formed on at least one surface of a flat negative electrode current collector, alternately stacked with an electrolyte layer containing a solid electrolyte; a flat electrode tab electrically connected to the power generation element; and an outer casing material housing the power generation element and the electrode tab with a portion of the electrode tab exposed to the outside. This secondary battery includes a heat transfer member in contact with the current collector and the outer casing material between the positive or negative electrode current collector at the outermost part of the stacking direction of at least one of the power generation elements and the outer casing material. The heat transfer member is 1 W / m·K or higher It is made of a thermally conductive resin, and a portion of it is bonded to the electrode tab. [Effects of the Invention]
[0008] According to the above embodiment, it is possible to provide a secondary battery that can improve heat dissipation performance while suppressing a decrease in energy density and an increase in cost. [Brief explanation of the drawing]
[0009] [Figure 1] Figure 1 is a cross-sectional view illustrating the secondary battery 1 according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view illustrating the secondary battery 1 according to modified example 1-1. [Figure 3] Figure 3 is a cross-sectional view illustrating the secondary battery 1 according to modified example 1-2. [Figure 4] Figure 4 is a cross-sectional view illustrating the secondary battery 1 according to modified examples 1-4. [Figure 5] Figure 5 is a cross-sectional view illustrating the secondary battery 1 according to the second embodiment. [Figure 6] Figure 6 is a cross-sectional view illustrating the secondary battery 1 according to modified example 2-1. [Figure 7] Figure 7 is a cross-sectional view illustrating the secondary battery 1 according to the third embodiment. [Figure 8]FIG. 8 is a cross-sectional view for explaining the secondary battery 1 according to the fourth embodiment. [Figure 9] FIG. 9 is a cross-sectional view for explaining the secondary battery 1 according to Modification 4-1.
Embodiments for Carrying Out the Invention
[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The sizes, ratios, etc. of each member in the drawings may be different from the actual ones. In the drawings, x indicates the short-side direction (also referred to as the width direction) of the secondary battery 1, y indicates the longitudinal direction of the secondary battery 1, and z indicates the stacking direction of the power generation elements 2.
[0011] [First Embodiment] In this embodiment, as the secondary battery 1, a flat stacked all-solid-state lithium-ion secondary battery will be exemplified and described.
[0012] FIG. 1 is a cross-sectional view for explaining the secondary battery 1 according to this embodiment. Note that FIG. 1 shows only a part on the positive electrode tab 5A side, and the negative electrode tab 5B side is omitted. In the following description, when there is no need to distinguish between the positive electrode tab 5A and the negative electrode tab 5B, they are referred to as the electrode tab 5. Similarly, for the current collector tab 10, when there is no need to distinguish between the positive electrode current collector tab 10A and the negative electrode current collector tab 10B (not shown), it is referred to as the current collector tab 10.
[0013] In the secondary battery 1, the power generation element 2 and the flat electrode tab 5 electrically connected to the power generation element 2 via the current collector tab 10 are housed in the exterior member 4 with a part of the electrode tab 5 led out to the outside.
[0014] The power generation element 2 consists of a positive electrode 6, on which a positive electrode active material layer 6B is formed on at least one surface of a flat positive electrode current collector 6A, and a negative electrode 8, on which a negative electrode active material layer 8B is formed on at least one surface of a flat negative electrode current collector 8A, which are alternately stacked with an electrolyte layer 7 containing a solid electrolyte. Figure 1 shows a state in which four power generation elements 2 are stacked by repeatedly stacking the positive electrode 6, electrolyte layer 7, and negative electrode 8, but the number of stacks is not limited to this.
[0015] Positive electrode 6 is prepared by weighing predetermined amounts of positive electrode active material, sulfide solid electrolyte, conductive additive, binder, and xylene, mixing them to make a slurry, applying this slurry to one or both sides of a carbon-coated aluminum foil, and then drying it.
[0016] The electrolyte layer 7 is prepared by weighing and mixing predetermined amounts of sulfide solid electrolyte, binder, and xylene to create a slurry, which is then applied to both sides of the SUS foil and dried.
[0017] The negative electrode 8 is prepared by weighing predetermined amounts of negative electrode active material (containing Ag and C), binder, and NMP, mixing them to make a slurry, coating one or both sides of a SUS foil with the slurry, and then drying it.
[0018] The current collector tab 10 is formed such that a portion of the positive electrode current collector 6A and the negative electrode current collector 8A protrudes from one side of the substantially rectangular positive electrode current collector 6A and the negative electrode current collector 8A. The current collector tab 10 may also be formed from a conductive material separate from the positive electrode current collector 6A and the negative electrode current collector 8A.
[0019] The electrode tabs 5 are formed, for example, with the positive electrode tab 5A being made of aluminum and the negative electrode tab 5B being made of nickel. In addition, the electrode tabs 5 have a smaller width dimension compared to the power generation element 2.
[0020] The outer casing material 4 is made of a so-called laminate film. The specific composition of the laminate film is not particularly limited, and any known composition used as the outer casing material 4 in the technical field of secondary batteries 1 can be applied. The outer casing material 4 and the electrode tab 5 are bonded together via an adhesive layer 9.
[0021] The secondary battery 1 is manufactured as follows. First, electrolyte layers 7 are placed on both sides of the positive electrode 6, and the electrolyte layers 7 are transferred to the positive electrode 6 by roll pressing to create a positive electrode / electrolyte layer laminate. Next, the positive electrode / electrolyte layer laminate and the negative electrode 8 are stacked and roll pressed to create a positive electrode / electrolyte layer / negative electrode laminate. After that, the positive electrode tab 5A is joined to the positive electrode current collector 6A and the negative electrode tab 5B is joined to the negative electrode current collector 8A by ultrasonic welding or the like, and the heat transfer member 3, described later, is placed in the outer casing 4 and vacuum sealed. The joint between the electrode tab 5 and the current collector tab 10 is provided at the end of the electrode tab 5 on the power generation element 2 side.
[0022] Now, let's explain the heat transfer component 3.
[0023] The heat transfer member 3 is made of a thermally conductive resin material and is positioned between the current collector (positive electrode current collector 6A in this embodiment) located on the outermost side of one stacking direction of the power generation element 2 and the outer casing material 4, in contact with the positive electrode current collector 6A and the outer casing material 4. It is desirable that the resin material used has a thermal conductivity of 1 W / mK or higher.
[0024] Furthermore, a portion of the heat transfer member 3 is bonded to the positive electrode tab 5A. In the following description, the portion bonded to the positive electrode tab 5A is referred to as the bonded portion 3A, the portion in contact with the outermost positive electrode current collector 6A in the stacking direction is referred to as the heat receiving portion 3C, and the area between the bonded portion 3A and the heat receiving portion 3C is referred to as the intermediate portion 3B. It is desirable that the contact area between the heat receiving portion 3C and the outermost positive electrode current collector 6A in the stacking direction be as large as possible. Therefore, in this embodiment, the heat receiving portion 3C is shaped to contact the entire surface of the outermost positive electrode current collector 6A in the stacking direction that faces the exterior material 4. As the electrode tab 5 has a smaller width dimension compared to the power generation element 2, the bonded portion 3A has a smaller width dimension compared to the heat receiving portion 3C. Also, from the viewpoint of efficiency in transferring heat received from the power generation element 2 to the electrode tab 5, it is desirable that the stacking dimension (i.e., thickness) of the heat transfer member 3 be 10 μm or more.
[0025] As described above, when the heat transfer member 3 is arranged, the heat generated in the power generation element 2 moves from the outermost positive electrode current collector 6A in the stacking direction to the heat receiving portion 3C of the heat transfer member 3, and from there moves to the positive electrode tab 5A via the intermediate portion 3B and the adhesive portion 3A, and is dissipated from the positive electrode tab 5A to the outside of the secondary battery 1. In other words, by providing the heat transfer member 3, a heat dissipation path is formed from the power generation element 2 to the outside via the positive electrode tab 5A, improving heat dissipation performance. Note that improvement in heat dissipation performance here means an increase in the amount of heat dissipated or an increase in the heat dissipation rate.
[0026] Incidentally, the higher the contact between the heat receiving section 3C and the positive electrode current collector 6A, the easier it is for the heat generated in the power generation element 2 to be transferred to the heat transfer member 3. Also, considering that heat is dissipated from the heat receiving section 3C to the outer casing material 4, it is desirable for the contact between the heat receiving section 3C and the outer casing material 4 to be high. For this reason, the heat transfer member 3 should have a hardness (for example, a Vickers hardness of 75 N / mm²) that can absorb any irregularities within the tolerance range on the contact surfaces of the heat receiving section 3C, the positive electrode current collector 6A, and the outer casing material 4. 2 It is desirable that the following conditions be met. Furthermore, from the standpoint of the degree of adhesion mentioned above, the overall hardness of the heat transfer member 3 does not need to be uniform, and the surface hardness of the heat receiving portion 3C may be lower than the hardness of the interior of the heat receiving portion 3C, the adhesive portion 3A, and the intermediate portion 3B.
[0027] In this embodiment, the current collector on the outermost side in one stacking direction is the positive electrode current collector 6A, and the heat transfer member 3 is bonded to the positive electrode tab 5A. However, the current collector may be the negative electrode current collector 8A, or the object to which the heat transfer member 3 is bonded may be the negative electrode tab 5B (not shown).
[0028] As described above, this embodiment provides a secondary battery comprising a power generation element 2 formed by alternately stacking a positive electrode 6, on one side of a flat positive electrode current collector 6A, on which a positive electrode active material layer 6B is formed, and a negative electrode 8, on one side of a flat negative electrode current collector 8A, on which a negative electrode active material layer 8B is formed, via an electrolyte layer 7 containing a solid electrolyte; a flat electrode tab 5 electrically connected to the power generation element 2; and an outer casing material 4 that houses the power generation element 2 and the electrode tab 5 with a portion of the electrode tab 5 exposed to the outside. Between the current collector (positive electrode current collector 6A in this embodiment) located at the outermost edge in one stacking direction of the power generation element 2 and the outer casing material 4, a heat transfer member 3 is provided that is in contact with the current collector 6A and the outer casing material 4. The heat transfer member 3 is made of a thermally conductive resin, and a portion of it is bonded to the electrode tab 5. This creates a heat transfer path from the heat transfer member 3 to the electrode tab 5, increasing the heat dissipation path for the heat generated in the power generation element 2, thereby improving heat dissipation performance. Furthermore, since the only additional component is the heat transfer element 3, it is possible to suppress the decrease in energy density caused by the enlargement of the secondary battery 1 and the increase in cost due to the increase in the number of components.
[0029] In this embodiment, the adhesive portion 3A has a smaller width dimension than the heat receiving portion 3C. That is, the contact area between the heat receiving portion 3C and the current collector and the exterior material 4 can be made larger.
[0030] In this embodiment, the surface hardness of the heat receiving portion 3C may be lower than the hardness of the interior of the heat receiving portion 3C, the adhesive portion 3A, and the intermediate portion 3B. This ensures good adhesion between the heat receiving portion 3C, the current collector 6A, and the exterior material 4.
[0031] Next, modifications of the first embodiment described above will be explained. Each of the modifications described below falls within the scope of the present invention, similar to the first embodiment.
[0032] (Example 1-1) Figure 2 is a cross-sectional view of a secondary battery 1 according to modification 1-1 of the first embodiment. In Figure 2, the negative electrode side is omitted, similar to Figure 1.
[0033] The secondary battery 1 in Modification 1-1 is basically the same as the secondary battery 1 shown in Figure 1, but the adhesive area of the adhesive portion 3A of the heat transfer member 3 is different. The differences will be explained below.
[0034] In Figure 1, the bonding area of the bonding portion 3A with the positive electrode tab 5A is the area of one surface of the positive electrode tab 5A that is exposed inside the outer casing material 4, excluding the bonding area with the positive electrode current collector 6A. In contrast, in Modification 1-1, the bonding area of the bonding portion 3A with the positive electrode tab 5A extends over the entire surface of one surface of the portion of the positive electrode tab 5A that is exposed inside the outer casing material 4. In other words, the heat transfer member 3 is also bonded to the bonding area between the positive electrode tab 5A and the positive electrode current collector 6A.
[0035] As a result, the area of the bonding region between the heat transfer element 3 and the positive electrode tab 5A becomes larger than in the configuration shown in Figure 1, further improving heat dissipation performance.
[0036] (Variations 1-2) Figure 3 is a cross-sectional view of a secondary battery 1 according to modification 1-2 of the first embodiment. In Figure 3, the negative electrode side is omitted, similar to Figure 1.
[0037] The secondary battery 1 in Modification 1-2 is basically the same as the secondary battery 1 in Modification 1-1 shown in Figure 2, but differs in that the positive electrode current collector tab 10A extending from the outermost positive electrode current collector 6A in the stacking direction is in close contact with the intermediate portion 3B of the heat transfer member 3. This difference will be explained below.
[0038] When the bonding area between the heat transfer member 3 and the positive electrode tab 5A widens as in Modified Example 1-2, the end of the intermediate portion 3B on the positive electrode tab 5A side (i.e., the boundary with the bonding portion 3A) becomes the end of the positive electrode tab 5A on the power generation element 2 side, and the inclination of the intermediate portion 3B with respect to the stacking direction becomes smaller compared to the configuration in Figure 1. As a result, the intermediate portion 3B and the positive electrode current collector tab 10A extending from the outermost positive electrode current collector 6A in the stacking direction come closer together.
[0039] Therefore, the intermediate portion 3B and the positive electrode current collector tab 10A extending from the outermost positive electrode current collector 6A in the stacking direction are brought into close contact (region A in Figure 3). In the first embodiment, the current collector tab 10 is only fixed at both ends, so it deforms and vibrates in response to volume changes of the negative electrode 8 due to charging and discharging, and input of external forces. In particular, the current collector tab 10 at the outermost end in the stacking direction has a large amount of deformation and amplitude. In this respect, by bringing it into close contact with the heat transfer member 3 as in the modified example 1-2, it is possible to ensure heat dissipation performance while mitigating deformation and vibration of the current collector tab 10.
[0040] (Variations 1-3) Figure 4 is a cross-sectional view of a secondary battery 1 according to a modified example 1-2 of the first embodiment. In Figure 4, the negative electrode side is omitted, similar to Figure 1.
[0041] The secondary battery 1 in Modification 1-3 is basically the same as the secondary battery 1 of the first embodiment shown in Figure 1, but the heat transfer member 3 is different. Specifically, while the heat transfer member 3 in Figure 1 has a uniform dimension (i.e., thickness) in the stacking direction, in Modification 1-3, the stacking direction dimension of the adhesive portion 3A is larger than the stacking direction dimension of the heat receiving portion 3C. In addition, the stacking direction dimension of the intermediate portion 3B gradually increases from the heat receiving portion 3C towards the adhesive portion 3A.
[0042] By configuring the heat transfer member 3 as described above, the heat capacity of the adhesive portion 3A is increased compared to the configuration in Figure 1. As a result, heat from the heat receiving portion 3C is more easily transferred to the adhesive portion 3A, and consequently, an effect equivalent to increasing the number of heat dissipation paths is obtained.
[0043] [Second Embodiment] Figure 5 is a cross-sectional view of the secondary battery 1 according to the second embodiment. In Figure 5, the negative electrode side is omitted, similar to Figure 1.
[0044] The secondary battery 1 according to this embodiment is a secondary battery 1 according to the first embodiment with an additional heat transfer member 3 provided. To distinguish this additional heat transfer member 3 from the heat transfer member 3 described in the first embodiment, the heat transfer member 3 described in the first embodiment is referred to as the first heat transfer member 3-1, and the heat transfer member 3 added in this embodiment is referred to as the second heat transfer member 3-2.
[0045] The heat receiving portion 3-2C of the second heat transfer member 3-2 is positioned between the positive electrode current collector 6A and the outermost positive electrode current collector 6A in the stacking direction, opposite to the first heat transfer member 3-1, and the outer casing material 4, in a state of contact with the positive electrode current collector 6A and the outer casing material 4. The adhesive portion 3-2A of the second heat transfer member 3-2 is bonded to the surface opposite to the surface to which the adhesive portion 3-1A of the positive electrode tab 5A is bonded, at a position facing the adhesive portion 3-1A.
[0046] In this embodiment, in addition to the same effects as in the first embodiment, the following further effects can be obtained. In this embodiment, heat transfer members 3 are provided between the positive or negative electrode current collectors 6A, 8A located at the outermost part of one stacking direction of the power generation element 2 and the outer casing material 4, and between the negative or positive electrode current collectors 8A, 6A located at the outermost part of the other stacking direction of the power generation element 2 and the outer casing material 4. When the heat transfer member 3 provided on the outermost part of one stacking direction is designated as the first heat transfer member 3-1, and the heat transfer member 3 provided on the outermost part of the other stacking direction is designated as the second heat transfer member 3-2, the first heat transfer member 3-1 is connected to one side of the electrode tab 5, and the second heat transfer member 3-2 is connected to the other side of the electrode tab 5. As a result, the heat dissipation path from the power generation element 2 to the positive electrode tab 5A is increased by the amount of the second heat transfer member 3-2 compared to the secondary battery 1 of the first embodiment, so the heat dissipation performance is further improved compared to the secondary battery 1 according to the first embodiment.
[0047] (Variation 2-1) Next, a modified example 2-1 of the second embodiment described above will be explained. Note that modified example 2-1 falls within the scope of the present invention, similar to the second embodiment.
[0048] Figure 6 is a cross-sectional view of a secondary battery 1 according to modification 2-1 of the second embodiment. In Figure 6, the negative electrode side is omitted, similar to Figure 1.
[0049] The secondary battery 1 according to Modification 2-1 differs from the secondary battery 1 according to the second embodiment in the position of the adhesive portion 3-2A. In the secondary battery 1 according to Modification 2-1, the adhesive portions 3-1A and 3-2A are offset in the longitudinal direction (i.e., in the direction perpendicular to the stacking direction).
[0050] If adhesive portions 3-1A and 3-2A are positioned opposite each other via the positive electrode tab 5A, heat will concentrate in the area of the positive electrode tab 5A where adhesive portions 3-1A and 3-2A are bonded, as heat is transferred from both sides. In contrast, if adhesive portions 3-1A and 3-2A are offset in the longitudinal direction, heat concentration will be suppressed, thereby preventing a localized temperature rise in the positive electrode tab 5A.
[0051] [Third Embodiment] Figure 7 is a cross-sectional view of the secondary battery 1 according to the third embodiment.
[0052] The secondary battery 1 according to this embodiment is the same as the secondary battery 1 according to the first embodiment in terms of the portion on the positive electrode tab 5A side, but differs in that the heat transfer member 3 is also bonded to the negative electrode tab 5B.
[0053] The heat transfer member 3 of this embodiment also has an intermediate portion 3B and an adhesive portion 3A on the negative electrode tab 5B side, similar to the positive electrode tab 5A side. Here, the adhesive portion 3A on the positive electrode tab 5A side is referred to as the positive electrode side adhesive portion 3A + , the same intermediate section 3B is the positive electrode side intermediate section 3B + The adhesive portion 3A on the negative electrode tab 5B side is the negative electrode side adhesive portion 3A - , the same intermediate section 3B is the negative electrode side intermediate section 3B - Let's assume that.
[0054] And the negative electrode side adhesive part 3A - It is attached to the negative electrode tab 5B.
[0055] With the above configuration, the heat received by the heat receiving section 3C from the power generation element 2 can be transferred to both the positive electrode tab 5A and the negative electrode tab 5B. In other words, the heat dissipation path is increased compared to the secondary battery 1 of the first embodiment. As a result, the heat dissipation performance is further improved compared to the secondary battery 1 of the first embodiment.
[0056] In this embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained. In this embodiment, the heat transfer member 3 is adhered to both the electrode tabs 5 of the positive electrode and the negative electrode. Thereby, the heat dissipation path increases more than that of the secondary battery 1 of the first embodiment, and the heat dissipation performance is further improved compared to the secondary battery 1 of the first embodiment.
[0057] [Fourth Embodiment] FIG. 8 is a cross-sectional view of the secondary battery 1 according to the fourth embodiment.
[0058] The secondary battery 1 according to this embodiment is the same as the secondary battery 1 according to the second embodiment in terms of the portion on the positive electrode tab 5A side, but is different in that the first heat transfer member 3-1 and the second heat transfer member 3-2 are also adhered to the negative electrode tab 5B respectively.
[0059] The first heat transfer member 3-1 and the second heat transfer member 3-2 of this embodiment each include an intermediate portion 3B and an adhesive portion 3A similar to those on the positive electrode tab 5A side on the negative electrode tab 5B side as well. Here, the adhesive portion 3-1A on the positive electrode tab 5A side of the first heat transfer member 3-1 is defined as the positive electrode side adhesive portion 3-1A + , the intermediate portion 3-1B therein is defined as the positive electrode side intermediate portion 3-1B + and the adhesive portion 3-1A on the negative electrode tab 5B side is defined as the negative electrode side adhesive portion 3-1A - , the intermediate portion 3-1B therein is defined as the negative electrode side intermediate portion 3-1B - . Similarly, for the second heat transfer member 3-2, the adhesive portion 3-2A on the positive electrode tab 5A side is defined as the positive electrode side adhesive portion 3-2A + , the intermediate portion 3-2B therein is defined as the positive electrode side intermediate portion 3-2B + and the adhesive portion 3-2A on the negative electrode tab 5B side is defined as the negative electrode side adhesive portion 3-2A - , the intermediate portion 3-2B therein is defined as the negative electrode side intermediate portion 3-2B - .
[0060] And the negative electrode side adhesive portion 3-1A - and the negative electrode side adhesive portion 3-2A - are each adhered to the negative electrode tab 5B.
[0061] With the above configuration, the heat received by the heat receiving portion 3-1C of the first heat transfer member 3-1 and the heat receiving portion 3-2C of the second heat transfer member 3-2 from the power generation element 2 can be transferred to both the positive electrode tab 5A and the negative electrode tab 5B. In other words, the heat dissipation path is increased compared to the secondary battery 1 of the second embodiment. As a result, the heat dissipation performance is further improved compared to the secondary battery 1 of the second embodiment.
[0062] In this embodiment, in addition to the same effects as in the second embodiment, the following further effects can be obtained. In this embodiment, the first heat transfer member 3-1 is connected to one side of the positive and negative electrode tabs 5, and the second heat transfer member 3-2 is connected to the other side of the positive and negative electrode tabs 5. As a result, the heat dissipation path is increased compared to the secondary battery 1 of the second embodiment. As a result, the heat dissipation performance is further improved compared to the secondary battery 1 of the second embodiment.
[0063] (Variation 4-1) Next, a modification 4-1 of the fourth embodiment described above will be explained. Note that the modification 4-1 described here also falls within the scope of the present invention, similar to the fourth embodiment.
[0064] Figure 9 is a cross-sectional view of the secondary battery 1 according to modified example 4-1.
[0065] In the secondary battery 1 according to the fourth embodiment, both the first heat transfer member 3-1 and the second heat transfer member 3-2 are bonded to both the positive electrode tab 5A and the negative electrode tab 5B. In contrast, in the secondary battery 1 according to modified example 4-1, the first heat transfer member 3-1 is connected to the positive electrode tab 5A, and the second heat transfer member 3-2 is connected to the negative electrode tab 5B. Alternatively, the first heat transfer member 3-1 may be bonded to the negative electrode tab 5B, and the second heat transfer member 3-2 may be bonded to the positive electrode tab 5A.
[0066] As described above, by configuring the first heat transfer member 3-1 and the second heat transfer member 3-2 to be bonded to different electrode tabs 5, a heat dissipation path can be formed that can suppress heat concentration on the electrode tabs 5.
[0067] It goes without saying that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical idea described in the claims. [Explanation of Symbols]
[0068] 1. Secondary battery, 2. Power generation element, 3. Heat transfer component, 4. Outer casing, 5. Electrode, 6. Positive electrode, 7. Electrolyte layer, 8. Negative electrode
Claims
1. A power generation element comprising a positive electrode having a positive electrode active material layer formed on at least one surface of a flat positive electrode current collector, and a negative electrode having a negative electrode active material layer formed on at least one surface of a flat negative electrode current collector, alternately stacked with an electrolyte layer containing a solid electrolyte in between, A flat electrode tab electrically connected to the power generation element, An exterior material that houses the power generation element and the electrode tab with a portion of the electrode tab exposed to the outside, In a secondary battery comprising the above, Between the positive or negative electrode current collector located at the outermost part of at least one of the power generation elements in the stacking direction and the outer casing material, a heat transfer member is provided that is in contact with the current collector and the outer casing material. A secondary battery characterized in that the heat transfer member is made of a resin having a thermal conductivity of 1 W / m·K or more, and a part of it is bonded to the electrode tab.
2. In the secondary battery according to claim 1, The heat transfer members are provided between the positive or negative electrode current collector at the outermost part of one of the power generation elements in the stacking direction and the outer casing material, and between the negative or positive electrode current collector at the outermost part of the other power generation element in the stacking direction and the outer casing material, respectively. A secondary battery in which, when the heat transfer member provided on the outermost side in the stacking direction of one stack is designated as the first heat transfer member, and the heat transfer member provided on the outermost side in the stacking direction of the other stack is designated as the second heat transfer member, the first heat transfer member is connected to one side of the electrode tab, and the second heat transfer member is connected to the other side of the electrode tab.
3. In the secondary battery described in claim 2, A secondary battery in which the connection portion between the first heat transfer member and the electrode tab, and the connection portion between the second heat transfer member and the electrode tab, are offset in a direction perpendicular to the stacking direction.
4. In the secondary battery according to claim 1, A secondary battery in which the heat transfer member is bonded to the electrode tabs of both the positive and negative electrodes.
5. In the secondary battery according to claim 1, The power generation element and the electrode tabs of the positive and negative electrodes are electrically connected by a portion of the current collector tabs, which are formed integrally with or separately from the current collectors of the positive and negative electrodes, being surface-bonded to the electrode tabs of the positive and negative electrodes, respectively. A secondary battery in which the bonding region between the heat transfer member and the electrode tab extends over the entire area of one side of the electrode tab exposed inside the outer material, including the bonding region between the current collector tab and the electrode tab.
6. In the secondary battery according to claim 5, When the heat transfer member is divided into an adhesive portion bonded to the electrode tab, a heat receiving portion in contact with the current collector at the outermost edge in the stacking direction, and an intermediate portion between the adhesive portion and the heat receiving portion, A secondary battery in which the current-collecting tab connecting the outermost current-collecting element in the stacking direction to the electrode tab is in close contact with the intermediate portion.
7. In the secondary battery according to claim 1, The heat transfer member is a secondary battery in which the stacking direction dimension of the adhesive portion to the electrode tab is larger than the stacking direction dimension of the portion in contact with the current collector at the outermost edge of the stacking direction.
8. In the secondary battery according to claim 1, The heat transfer members are provided between the positive or negative electrode current collector at the outermost part of one of the power generation elements in the stacking direction and the outer casing material, and between the negative or positive electrode current collector at the outermost part of the other power generation element in the stacking direction and the outer casing material, respectively. A secondary battery in which, when the heat transfer member provided on the outermost side in the stacking direction of one electrode is designated as the first heat transfer member, and the heat transfer member provided on the outermost side in the stacking direction of the other electrode is designated as the second heat transfer member, the first heat transfer member is connected to one surface of the electrode tabs of the positive electrode and the negative electrode, and the second heat transfer member is connected to the other surface of the electrode tabs of the positive electrode and the negative electrode.
9. In the secondary battery according to claim 1, The heat transfer members are provided between the positive or negative electrode current collector at the outermost part of one of the power generation elements in the stacking direction and the outer casing material, and between the negative or positive electrode current collector at the outermost part of the other power generation element in the stacking direction and the outer casing material, respectively. A secondary battery in which, when the heat transfer member provided on the outermost side in the stacking direction of one stack is designated as the first heat transfer member, and the heat transfer member provided on the outermost side in the stacking direction of the other stack is designated as the second heat transfer member, the first heat transfer member is connected to either the positive electrode or the negative electrode tab, and the second heat transfer member is connected to either the positive electrode or the negative electrode tab.
10. In the secondary battery according to claim 1, The heat transfer member is divided into an adhesive portion that is bonded to the electrode tab, a heat receiving portion that is in contact with the current collector at the outermost part in the stacking direction, and an intermediate portion between the adhesive portion and the heat receiving portion. When the width direction is defined as the direction perpendicular to the stacking direction and perpendicular to the direction in which the electrode tabs and the power generation elements are aligned, A secondary battery in which the adhesive portion has a smaller width dimension than the heat receiving portion.
11. In the secondary battery according to claim 1, When the heat transfer member is divided into an adhesive portion bonded to the electrode tab, a heat receiving portion in contact with the current collector at the outermost edge in the stacking direction, and an intermediate portion between the adhesive portion and the heat receiving portion, A secondary battery in which the surface hardness of the heat receiving portion is lower than the hardness of the interior of the heat receiving portion, the adhesive portion, and the intermediate portion.