A heat dissipation structure for a power battery and a power battery

Abstract

The present invention provides a heat dissipation structure for a power battery, which includes a reaction body, a housing, and electrode plates. The reaction body includes a positive electrode material, a negative electrode material, and an electrolyte packaged in a wound or laminated manner, and further includes a heat dissipation layer. The contact surface between the reaction body and the inner wall of the housing is a covering surface, and the heat dissipation layer is tightly filled between the covering surface and the inner wall of the housing. The heat dissipation layer is a liquid metal. When the temperature of the reaction body rises due to the power generation reaction, the heat dissipation layer melts with the increase in temperature and can flow between the covering surface and the inner wall of the housing, and the heat dissipation layer is always located between the covering surface and the inner wall of the housing under the action of the surface tension of the liquid metal. By utilizing the heat conduction performance of the liquid metal, the efficiency of conducting the reaction heat of the reaction body to the housing for diffusion can be improved. At the same time, by utilizing the characteristic that the liquid metal can flow when heated and melted, the liquid metal fills the unevenness between the covering surface and the inner wall of the housing, avoiding the problem that air bubbles hinder heat conduction.

Description

Technical Field

[0001] The present invention relates to the technical field of battery heat dissipation, and particularly to a heat dissipation structure for a power battery and a power battery. Background Art

[0002] To meet the requirements of the automotive, energy storage and other industries for battery technologies with large capacity and high power, at present, due to the limited small capacity and low power of single battery cells, battery cells are usually connected in series and parallel to form battery packs for use. Due to the electrochemical properties of the battery itself, a large amount of heat is released during battery operation, resulting in an increase in the temperature of the battery pack. Long-term operation of the battery at high temperatures or large temperature differences will reduce its available capacity and accelerate life attenuation, while efficient battery heat dissipation technology can effectively reduce the operating temperature of the battery pack and reduce the temperature difference between single cells, which is of great significance for improving the available capacity and life of the battery pack.

[0003] Currently, the research on battery heat dissipation technology mainly focuses on modular battery packs, and the main heat dissipation methods include air cooling, liquid cooling, phase change material cooling, and air-conditioning cooling, etc. Among them, with the in-depth research, the method of using liquid metal for liquid cooling has gradually attracted the attention of technicians.

[0004] However, the method of using liquid metal for liquid cooling only simply improves the efficiency of heat diffusion, but cannot fundamentally improve the heat dissipation performance of single battery cells. Therefore, it will still cause inconsistent heat diffusion effects in different parts of the battery pack, as well as problems such as low liquid cooling heat dissipation efficiency and high cost. Summary of the Invention

[0005] In view of this, the present invention proposes a heat dissipation structure for a power battery and a power battery that can effectively improve the heat dissipation performance of single battery cells.

[0006] The technical solution of the present invention is realized as follows: The present invention provides a heat dissipation structure for a power battery, including a reaction body, a housing, and electrode plates. The reaction body includes a positive electrode material, a negative electrode material, and an electrolyte packaged in a wound or laminated manner, and the reaction body is used for power generation reactions. The housing tightly wraps around the outside of the reaction body, and the electrode plates are fixedly installed on the housing. The electrode plates include positive and negative electrode plates and are respectively electrically connected to the positive electrode material and the negative electrode material of the reaction body. It further includes a heat dissipation layer. The contact surface between the reaction body and the inner wall of the housing is a sticking surface, and the heat dissipation layer is tightly filled between the sticking surface and the inner wall of the housing. The heat dissipation layer is liquid metal; when the reaction body heats up due to power generation reactions, the heat dissipation layer melts as the temperature rises and can flow between the sticking surface and the inner wall of the housing, and the heat dissipation layer is always located between the sticking surface and the inner wall of the housing under the action of the surface tension of the liquid metal.

[0007] On the basis of the above technical solution, preferably, the heat dissipation layer is tightly attached to the inner wall of the housing and is in close contact with the sticking surface by spraying or smearing.

[0008] Based on the above technical solutions, preferably, when the reaction body is packaged in a wound manner, the attachment surface is the entire outer surface of the reaction body around the winding axis of the reaction body.

[0009] Based on the above technical solutions, preferably, when the reaction body is packaged in a laminated manner, the attachment surfaces are the end faces of the two outer surfaces of the reaction body parallel to the lamination plane.

[0010] More preferably, the area of the inner wall of the housing covered by the heat dissipation layer does not exceed the area of the attachment surface.

[0011] Based on the above technical solutions, preferably, the liquid metal is a gallium-based room-temperature liquid metal.

[0012] More preferably, the liquid metal is gallium, a gallium-indium alloy, a gallium-indium-tin alloy, or a gallium-indium-tin-zinc alloy.

[0013] Based on the above technical solutions, preferably, the thickness of the heat dissipation layer is 300 nm to 500 nm.

[0014] In a second aspect, the present invention provides a power battery, and the power battery adopts the above heat dissipation structure.

[0015] The heat dissipation structure of a power battery and the power battery of the present invention have the following beneficial effects compared with the prior art:

[0016] (1) The present invention provides a heat dissipation layer between the attachment surface and the inner wall of the housing, and the heat dissipation layer is a liquid metal. By using the heat conduction performance of the liquid metal, the efficiency of conducting the reaction heat of the reaction body to the housing for diffusion can be improved. At the same time, by using the property that the liquid metal melts when heated and can flow, the liquid metal fills the unevenness between the attachment surface and the inner wall of the housing, avoiding the problem that air bubbles hinder heat conduction.

[0017] (2) The heat dissipation layer is applied to the inner wall of the housing and pressed on the attachment surface by means of coating or spraying. At the same time, the coverage area of the heat dissipation layer is set not to exceed the attachment surface, so that the liquid metal can flow freely in the gap between the inner wall of the housing and the attachment surface, and will not overflow from the gap.

[0018] (3) By limiting the thickness of the heat dissipation layer, the liquid metal can avoid overflowing from the gap between the inner wall of the housing and the attachment surface due to the action of its own surface tension. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] Figure 1 It is a side sectional view of the cooling structure of the battery packaged in a winding manner according to the present invention;

[0021] Figure 2 It is a side sectional view of the cooling structure of the battery packaged in a stacked manner according to the present invention.

[0022] In the figure: 1, reaction body; 11, adhering surface; 2, housing; 3, heat dissipation layer; 4, electrode plate. Specific embodiments

[0023] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0024] A heat dissipation structure of a power battery according to the present invention includes a reaction body 1, a housing 2, and an electrode plate 4. The reaction body 1 includes a positive electrode material, a negative electrode material, and an electrolyte packaged in a winding manner or a stacked manner. The reaction body 1 is used for power generation reaction. The housing 2 is tightly wrapped outside the reaction body 1. The electrode plate 4 is fixedly installed on the housing 2. The electrode plate 4 includes positive and negative electrode plates and is electrically connected to the positive electrode material and the negative electrode material of the reaction body 1 respectively. It further includes a heat dissipation layer 3.

[0025] Among them, the contact surface between the reaction body 1 and the inner wall of the housing 2 is the adhering surface 11. The heat dissipation layer 3 is tightly filled between the adhering surface 11 and the inner wall of the housing 2. The heat dissipation layer 3 is a liquid metal. Among them, the liquid metal is a gallium-based room-temperature liquid metal. Compared with the common aluminum shell or aluminum plastic film of the existing battery housing 2, the gallium-based alloy has better heat conduction performance, thereby improving the heat conduction efficiency.

[0026] When the above technical solution is adopted, when the temperature of the reaction body 1 increases due to the power generation reaction, the heat dissipation layer 3 melts as the temperature rises and can flow between the attachment surface 11 and the inner wall of the housing 2, and the heat dissipation layer 3 is always located between the attachment surface 11 and the inner wall of the housing 2 under the action of the surface tension of the liquid metal, thereby improving the heat dissipation efficiency inside the battery cell; at the same time, when the heat dissipation layer 3 is arranged between the inner wall of the housing 2 and the attachment surface 11, the liquid metal will be heated and melted, so as to flow and fill the surface pits of the inner wall of the housing 2 and the attachment surface 11, removing air bubbles or confining air bubbles in the liquid metal, thereby eliminating adverse factors hindering heat conduction and improving the efficiency of heat conduction, and further fundamentally improving the heat dissipation performance of the battery cell.

[0027] As Figure 1 shown, when the reaction body 1 is packaged in a winding manner, the attachment surface 11 is the entire outer surface of the reaction body 1 around the winding axis of the reaction body 1.

[0028] As Figure 1 shown, when the reaction body 1 is packaged in a stacked sheet manner, the attachment surface 11 is the two outer surface end faces of the reaction body 1 parallel to the stacked sheet plane.

[0029] Among them, the area of the heat dissipation layer 3 covering the inner wall of the housing 2 does not exceed the area of the attachment surface 11, so as to avoid the problem of overflow caused by the increase in volume due to thermal expansion and contraction after the liquid metal is heated and melted.

[0030] As a further improvement of the present invention, the thickness of the heat dissipation layer 3 is limited to 300 nm to 500 nm, so that the liquid metal can avoid overflowing from the gap between the inner wall of the housing 2 and the attachment surface 11 through the action of its own surface tension.

[0031] As an alternative embodiment, the heat dissipation layer 3 is closely attached to the inner wall of the housing 2 and closely contacts the attachment surface 11 by spraying or smearing, which is suitable for large-scale and standardized industrial production.

[0032] As an alternative embodiment, the liquid metal is gallium, gallium-indium alloy, gallium-indium-tin alloy or gallium-indium-tin-zinc alloy, specifically it can be Ga 68 In 20 Sn 12 or Ga 67 In 20.5 Sn 12.5 .

[0033] On the other hand, a power battery adopts the above heat dissipation structure.

[0034] Working principle:

[0035] The reaction body 1 undergoes a discharge reaction and generates heat to increase the temperature, and the heat is conducted to the housing 2 through the heat dissipation layer 3, and heat diffusion is carried out to achieve heat dissipation and cooling.

[0036] In this process, since the heat dissipation layer 3 is made of liquid metal, especially gallium-based alloy, compared with the common aluminum shell or aluminum plastic film of the existing battery case 2, the gallium-based alloy has better heat conduction performance, thus improving the efficiency of heat conduction.

[0037] In addition, the inner wall of the battery case 2 and the attachment surface 11 are both ideally flat surfaces. However, in actual production, due to technical limitations, there are inevitably many pits or uneven surfaces that are invisible to the naked eye on the surfaces of the two. Therefore, when the inner wall of the case 2 and the attachment surface 11 are attached to each other, there will inevitably be air bubbles between them. The air bubbles have a certain heat insulation effect and hinder the heat conduction.

[0038] When the liquid metal heat dissipation layer 3 is arranged between the inner wall of the case 2 and the attachment surface 11, the liquid metal will be heated and melted, and thus flow and fill the surface pits of the inner wall of the case 2 and the attachment surface 11, excluding the air bubbles or confining the air bubbles in the liquid metal, thereby eliminating the adverse factors hindering heat conduction, improving the efficiency of heat conduction, and further fundamentally improving the heat dissipation performance of the battery cell.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A power battery, comprising a reaction body (1), a housing (2) and electrode plates (4). The reaction body (1) includes a positive electrode material, a negative electrode material and an electrolyte packaged in a wound or laminated manner. The reaction body (1) is used for power generation reactions. The housing (2) tightly wraps around the outside of the reaction body (1). The electrode plates (4) are fixedly installed on the housing (2). The electrode plates (4) include positive and negative electrode plates and are electrically connected to the positive electrode material and the negative electrode material of the reaction body (1) respectively. It is characterized in that: It further includes a heat dissipation layer (3). The contact surface between the reaction body (1) and the inner wall of the housing (2) is a covering surface (11). When the reaction body (1) is packaged in a wound manner, the covering surface (11) is the entire outer surface of the reaction body (1) around the winding axis of the reaction body (1); when the reaction body (1) is packaged in a laminated manner, the covering surface (11) is the end surfaces of the outer surfaces of two reaction bodies (1) parallel to the lamination plane. The heat dissipation layer (3) is tightly filled between the covering surface (11) and the inner wall of the housing (2). The heat dissipation layer (3) is a liquid metal; the heat dissipation layer (3) is tightly attached to the inner wall of the housing (2) by spraying or smearing and is in close contact with the covering surface (11); the area of the heat dissipation layer (3) covering the inner wall of the housing (2) does not exceed the area of the covering surface (11); the thickness of the heat dissipation layer (3) is 300 nm to 500 nm. The liquid metal is gallium, gallium-indium alloy, gallium-indium-tin alloy or gallium-indium-tin-zinc alloy. When the temperature of the reaction body (1) rises due to the power generation reaction, the heat dissipation layer (3) melts with the increase in temperature and can flow between the covering surface (11) and the inner wall of the housing (2), and the heat dissipation layer (3) is always located between the covering surface (11) and the inner wall of the housing (2) under the action of the surface tension of the liquid metal.

Images