Battery pack and vehicle

Abstract

The invention discloses a battery pack and a vehicle, the battery pack comprises a battery cell assembly and a heating film, the battery cell assembly comprises a plurality of battery cells, the plurality of battery cells are sequentially arranged along a first direction, the length direction of the battery cells is a second direction, the heating film is arranged on at least one side of the second direction of the plurality of battery cells, and in the first direction, the heating film is arranged between the plurality of battery cells. The heating power of the two ends of the heating film is higher than that of the middle, and the first direction is perpendicular to the second direction. According to the battery pack, the heating film is arranged on one side of the battery cell assembly, so that the heating film can heat the battery cells, and the heating power at the two ends of the heating film is higher than that in the middle, so that the plurality of battery cells can be uniformly heated, and the charge-discharge performance and the material activity of the battery pack can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and more particularly to a battery pack and a vehicle. Background Art

[0002] At present, the development of new energy vehicles in China is changing with each passing day, and the number of new energy vehicles in the market is increasing. As one of the core components of new energy vehicles, lithium-ion power batteries have become the focus of attention in the market and technology fields. As the environmental temperature decreases, the viscosity of the electrolyte increases and the material activity decreases for lithium-ion power batteries. During charging and discharging, the polarization of the battery increases, and the released capacity and energy both decay. Moreover, the lower the temperature drops, the greater the degree of decay. To solve the problem of decay of lithium-ion power batteries at low temperatures, they often need to be heated.

[0003] In related technologies, the performance of lithium-ion power batteries deteriorates at low temperatures, especially the decay of the charging acceptance ability is relatively serious. Therefore, they can only be normally charged after being heated to a suitable temperature (such as above 0°C). A layer of copper or stainless steel heating wire wrapped with polyimide is pasted and covered on the side of the battery module. After the heating wire is powered on, it generates heat, and the heat is input to the battery cells through heat conduction. Since the battery module is usually stacked by battery cells of the same specification, the heat dissipation conditions of the battery cells at different stacking positions are not the same. For example, the battery cells in the middle of the module have slower heat dissipation than those at the outermost edge because there are battery cells on both sides. During the heating process, the temperature rise will be faster; while for the battery cells at the outermost edge, one side is a battery cell and the other side is an end plate. The heat dissipation condition of the end plate is better than that of the battery cell, which will cause the battery cells at the edge position to heat up more slowly, resulting in a large temperature difference between the battery cells. In the most serious case, the battery cells in the middle may already require over-temperature protection, while the battery cells at the edge have not yet reached the temperature allowed for charging. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, an object of the present invention is to provide a battery pack that has uniform heating, thereby reducing the temperature difference between battery cells, and further improving the charge and discharge performance and material activity of the battery pack.

[0005] The present invention further provides a vehicle.

[0006] The battery pack according to the present invention includes: a battery cell assembly and a heating film. The battery cell assembly includes: a plurality of battery cells arranged in sequence along a first direction, the length direction of the battery cells being a second direction. The heating film is disposed on at least one side of the plurality of battery cells in the second direction, and in the first direction, the heating power at both ends of the heating film is higher than that at the middle, and the first direction is perpendicular to the second direction.

[0007] According to the battery pack of the present invention, by providing a heating film on one side of the battery cell assembly, the heating film can heat the battery cells, and the heating power at both ends of the heating film is higher than that in the middle, so that multiple battery cells can be heated evenly, thereby improving the charge and discharge performance of the battery pack and the material activity.

[0008] In some examples of the present invention, the heating film includes: a plurality of heating units, which are connected in sequence in a first direction, and the plurality of heating units are respectively arranged in one-to-one correspondence with the plurality of battery cells, and the heating power of the heating units at both ends is higher than that of the heating units in the middle.

[0009] In some examples of the present invention, the battery pack further includes: end plates, which are respectively arranged at both ends of the battery cell assembly in the first direction.

[0010] In some examples of the present invention, the battery pack further includes: a spacer, which is arranged between the battery cells at both ends in the first direction and the end plates.

[0011] In some examples of the present invention, the heating power at the battery cells at both ends in the first direction is P1, and the heating power at the battery cells in the middle in the first direction is P2. P1 and P2 satisfy the relationship: ΔP = P1 - P2, and ΔP = (ΔT × S × k) / (δ1 / λ1 + δ1 / λ2……+ δn / λn); where, the temperature difference between the battery cells at both ends in the first direction and the end plates is ΔT, the contact area between the spacer and the battery cells is S, the redundancy coefficient is k, the spacer is at least one, the thicknesses of the spacers are δ1, δ2…δn respectively, and the thermal conductivities of the spacers are λ1, λ2…λn respectively.

[0012] In some examples of the present invention, the value range of k is: 1 ≤ k ≤ 1.3.

[0013] In some examples of the present invention, the battery pack further includes: a box body and a cover plate. In a third direction, the box body is arranged on one side of the battery cell assembly, and the cover plate is covered on the other side of the battery cell assembly. The first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0014] In some examples of the present invention, the battery pack further includes: thermal conductive glue, and one side of the battery cell assembly is bonded to the box body through the thermal conductive glue.

[0015] In some examples of the present invention, there is a gap between adjacent two battery cells; or an insulating member is arranged between adjacent two battery cells.

[0016] According to the vehicle of the present invention, it includes: the above-mentioned battery pack.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 is an exploded view of a battery pack according to an embodiment of the present invention.

[0020] Reference Numerals:

[0021] 100, battery pack;

[0022] 10, battery cell assembly; 11, battery cell; 20, heating film; 21, heating unit; 30, end plate; 40, box body; 50, cover plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Embodiments of the present invention will be described in detail below. The embodiments described with reference to the drawings are exemplary. Embodiments of the present invention will be described in detail below.

[0024] Reference will be made below to Figure 1 describe a battery pack 100 according to an embodiment of the present invention, which is applied to a vehicle.

[0025] As Figure 1 shown, the battery pack 100 according to the present invention includes: a battery cell assembly 10 and a heating film 20. The battery cell assembly 10 includes: a plurality of battery cells 11, and the plurality of battery cells 11 are arranged in sequence along a first direction. The length direction of the battery cell 11 is a second direction. The heating film 20 is disposed on at least one side of the plurality of battery cells 11 in the second direction, and in the first direction, the heating power at both ends of the heating film 20 is higher than that at the middle portion. The first direction is perpendicular to the second direction.

[0026] It can be understood that the first direction is the left-right direction of the battery pack 100, the second direction is the front-back direction of the battery pack 100, and the plurality of battery cells 11 are arranged in sequence along the left-right direction, so that the plurality of battery cells 11 can be concentrated, and the plurality of battery cells 11 can form a series structure, thereby ensuring the storage capacity of the battery pack 100. The heating film 20 is disposed on the front side or the rear side of the plurality of battery cells 11 and can be installed according to actual conditions, so that the heating film 20 can heat the plurality of battery cells 11, thereby ensuring that the plurality of battery cells 11 are heated to a suitable temperature. Moreover, the heating power of the heating film 20 at the left and right ends is higher than that of other heating films 20, so that each battery cell 11 can be heated, and thus the plurality of battery cells 11 can be heated evenly.

[0027] Thus, by providing a heating film 20 on one side of the battery cell assembly 10, the heating film 20 can heat the battery cells 11. Moreover, the heating power at both ends of the heating film 20 is higher than that at the middle, so that multiple battery cells 11 can be evenly heated, thereby improving the charge and discharge performance of the battery pack 100 and the material activity.

[0028] Among them, as Figure 1 shown, the heating film 20 includes: a plurality of heating units 21. In the first direction, the plurality of heating units 21 are connected in sequence, and the plurality of heating units 21 are respectively arranged in one-to-one correspondence with the plurality of battery cells 11. The heating power of the heating units 21 at both ends is higher than that of the heating units 21 in the middle. That is to say, the plurality of heating units 21 are arranged in sequence along the left-right direction, so that the heating units 21 can form a series structure, and one heating unit 21 can correspond to one battery cell 11, so that each battery cell 11 can be heated. Moreover, the heating power of the heating units 21 at the left and right ends is higher than that of other heating units 21, so that multiple battery cells 11 can be evenly heated, thereby improving the charge and discharge performance of the battery pack 100 and the material activity.

[0029] In addition, as Figure 1 shown, the battery pack 100 further includes: end plates 30. In the first direction, the end plates 30 are respectively arranged at both ends of the battery cell assembly 10. It can be understood that the end plates 30 are located on the left and right sides of the battery cell assembly 10. Such an arrangement can make the end plates 30 close to the battery cells 11 at both ends, and the battery cells 11 close to the end plates 30 have a higher heat dissipation efficiency than the battery cells 11 far from the end plates 30, resulting in a slower heating rate of the battery cells 11 at both ends. The heating power of the heating units 21 at both ends is higher than that of other heating units 21, so that multiple battery cells 11 can be evenly heated, thereby improving the charge and discharge performance of the battery pack 100 and the material activity. For example, the end plates 30 are made of aluminum alloy material, which can ensure the overall structural strength of the battery pack 100. The heat lost by the battery cells 11 close to the end plates 30 at the end plates 30 can be compensated by the heating units 21 at both ends, so that the temperatures of multiple battery cells 11 are more uniform.

[0030] Furthermore, as Figure 1 shown, the battery pack 100 further includes: a separator. The separator is arranged between the battery cells 11 and the end plates 30 at both ends in the first direction. That is to say, the separator is located between the left-end battery cell 11 and the end plate 30, and between the right-end battery cell 11 and the end plate 30, so that the heat conduction rate between the battery cell assembly 10 and the end plates 30 can be improved, and further the heat dissipation efficiency of the battery pack 100 can be improved. For example, the separator is one of an insulating member, a heat insulating member or a structural member, so that the heat conduction rate between the battery cell assembly 10 and the end plates 30 can be improved.

[0031] Among them, as Figure 1 shown, the heating power at the battery cells 11 at both ends in the first direction is P1, and the heating power at the battery cells 11 in the middle in the first direction is P2. P1 and P2 satisfy the relational expression: ΔP = P1 - P2, and ΔP = (ΔT × S × k) / (δ1 / λ1 + δ1 / λ2……+ δn / λn); where, the temperature difference between the battery cells 11 at both ends in the first direction and the end plate 30 is ΔT, the contact area between the separator and the battery cells 11 is S, the redundancy coefficient is k, the separator is at least one, the thicknesses of the separators are δ1, δ2…δn respectively, the thermal conductivities of the separators are λ1, λ2…λn respectively, and the value range of k is: 1 ≤ k ≤ 1.3.

[0032] Thus, multiple heating units 21 form a series structure, so that there is no need to separately control the opening and closing of the heating units 21, nor is it necessary to know the temperature of each battery cell 11 corresponding to the heating unit 21 in real time. It only needs to measure data such as ΔT, S, and the design parameters δ, λ of the battery module during the heating test to implement, so as to achieve the purpose of uniformly heating multiple battery cells 11. Such a setting can reduce the heating complexity of the battery pack 100, thereby reducing costs and having good implementability.

[0033] In addition, as Figure 1 shown, the battery pack 100 further includes: a box body 40 and a cover plate 50. In the third direction, the box body 40 is arranged on one side of the battery cell assembly 10, and the cover plate 50 is covered on the other side of the battery cell assembly 10. The first direction, the second direction, and the third direction are perpendicular to each other in pairs. It can be understood that the third direction is the up and down direction, the box body 40 is located below the battery cell assembly 10, and the cover plate 50 is located above the battery cell assembly 10, so that the box body 40, the cover plate 50, and the end plate 30 can form an installation space, and then it is convenient to arrange the battery cell assembly 10 in the installation space. For example, the box body 40 is made of a metal material, so as to improve the heat dissipation efficiency between the lower surface of the battery cell assembly 10 and the box body 40, and the cover plate 50 is made of a plastic material, so as to achieve the lightweight design of the battery pack 100 and save costs.

[0034] In addition to this, as Figure 1 shown, the battery pack 100 further includes: a thermal conductive adhesive. One side of the battery cell assembly 10 is bonded to the box body 40 through the thermal conductive adhesive. That is to say, the thermal conductive adhesive is located between the lower surface of the battery cell assembly 10 and the box body 40, so as to improve the heat dissipation efficiency between the lower surface of the battery cell assembly 10 and the box body 40, and further improve the performance of the battery pack 100.

[0035] Optionally, as Figure 1As shown, adjacent two battery cells 11 are spaced apart from each other, or an insulating member is provided between adjacent two battery cells 11. It can be understood that adjacent two battery cells 11 can be spaced apart from each other, so that a gap can be formed between adjacent two battery cells 11, or an insulating member can be provided between adjacent two battery cells 11, so that each battery cell 11 can be relatively independent, and thus it is convenient for the installation and disassembly of the battery cells 11, as well as the maintenance and repair.

[0036] The vehicle according to the present invention includes: the battery pack 100 of the above embodiment. By providing the heating film 20 on one side of the battery cell assembly 10, the heating film 20 can heat the battery cells 11, and the heating power at both ends of the heating film 20 is higher than that at the middle, so that multiple battery cells 11 can be heated evenly, and thus the charge and discharge performance of the battery pack 100 and the material activity can be improved.

[0037] In the description of the present invention, the "first feature" and "second feature" may include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more. In the description of the present invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. In the description of the present invention, the first feature being "above", "above" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0039] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery pack, characterized in that: include: A battery cell assembly (10), the battery cell assembly (10) comprising: a plurality of battery cells (11), the plurality of battery cells (11) being arranged in sequence along a first direction; A heating film (20), wherein the length direction of the battery cell (11) is a second direction, the heating film (20) is arranged on at least one side of the second direction of the plurality of battery cells (11), and in the first direction, the heating power at both ends of the heating film (20) is higher than the heating power in the middle, and the first direction is arranged perpendicular to the second direction.

2. The battery pack according to claim 1, characterized in that: The heating film (20) comprises: a plurality of heating units (21); in a first direction, the plurality of heating units (21) are connected in sequence, and the plurality of heating units (21) are respectively arranged in one-to-one correspondence with the plurality of battery cells (11); the heating power of the heating units (21) located at the two ends is higher than the heating power of the heating units (21) located in the middle.

3. The battery pack according to claim 1, characterized in that: Also includes: End plates (30), in a first direction, the end plates (30) are respectively arranged at two ends of the battery core assembly (10).

4. The battery pack according to claim 3, characterized in that: Also includes: An isolating member is disposed between the battery core (11) and the end plate (30) at two ends in a first direction.

5. The battery pack according to claim 4, characterized in that: The heating power at the battery core (11) located at both ends of the first direction is P1, and the heating power at the battery core (11) located in the middle of the first direction is P2, and P1 and P2 satisfy the relationship: ΔP=P1-P2, and ΔP=(ΔT×S×k) / (δ1 / λ1+δ1 / λ2…+δn / λn); The temperature difference between the battery cell (11) and the end plate (30) at two ends of the first direction is ΔT, the contact area between the isolating element and the battery cell (11) is S, the redundancy coefficient is k, there is at least one isolating element, the thicknesses of the isolating elements are δ1, δ2…δn, and the thermal conductivity coefficients of the isolating elements are λ1, λ2…λn, respectively.

6. The battery pack according to claim 5, characterized in that: The value range of k is: 1≤k≤1.

3.

7. The battery pack according to claim 1, characterized in that: Also includes: The box body (40) and the cover plate (50) are arranged on one side of the battery cell assembly (10) in the third direction, and the cover plate (50) is arranged on the other side of the battery cell assembly (10), and the first direction, the second direction and the third direction are arranged perpendicularly in pairs.

8. The battery pack according to claim 7, characterized in that: Also includes: Thermally conductive adhesive, one side of the battery core assembly (10) is bonded to the box body (40) via the thermally conductive adhesive.

9. The battery pack according to claim 1, characterized in that: Two adjacent battery cells (11) are arranged at a distance from each other; or An insulating member is provided between two adjacent battery cells (11).

10. A vehicle, characterized in that: include: The battery pack (100) according to any one of claims 1 to 9.

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