Battery pack containing different types of battery cells

Abstract

The present invention relates to a battery pack including heterogeneous battery cells, and more specifically, to a battery pack including: a first battery module including a plurality of first battery cells; a second battery module including a plurality of second battery cells; a pack housing including an accommodating section in which both the first battery module and the second battery module are accommodated; a partition section forming an inner wall of the accommodating section; and a pack BMS (Battery Management System) that controls the usable capacity of the first battery module and the usable capacity of the second battery module so that they are the same or similar, and the second battery module is capable of cooling the first battery module.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0133603 filed on October 17, 2022 and Korean Patent Application No. 10-2023-0103738 filed on August 8, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery pack including heterogeneous battery cells. [Background technology]

[0003] A secondary battery generally refers to a rechargeable battery that can be used as a power source for small home appliances such as mobile phones, laptops, and camcorders, as well as for vehicles such as automobiles. One type of secondary battery that can be used as a power source for automobiles is the lithium secondary battery. Lithium secondary batteries generally have high performance and high stability, and are manufactured using materials selected according to the desired characteristics, such as battery life, charge / discharge capacity, charge / discharge speed, temperature characteristics, and stability.

[0004] In particular, as electric vehicle technology continues to improve, battery packs, one of the three core components of electric vehicles, play a vital role in the performance of electric vehicles. Currently, user demand for electric vehicles is increasing, and so is the need for battery energy density. Regarding the battery packs installed in electric vehicles, active research is being conducted to increase the energy density of battery cells in order to increase the driving range of electric vehicles. It is generally known that increasing the specific gravity of nickel in battery cells improves energy density.

[0005] However, batteries with a high nickel content in the battery cells tend to generate a lot of heat, posing safety concerns. In particular, when a battery pack is manufactured using a battery module including only battery cells with a high nickel content, heat is generated simultaneously in multiple battery cells as the battery cells are used, resulting in a problem of reduced performance of the battery cells due to the heat generated.

[0006] Therefore, there is a need to develop a technology to solve the above problems. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention is intended to solve the above problems, and by accommodating a first battery module and a second battery module, each including different types of battery cells, in a single battery pack, one of the first battery module and the second battery module, which have different heat generation amounts per unit volume, is cooled by the other battery module, and controlling the usable capacities of the first battery module and the second battery module to be maintained at the same or similar levels, the present invention can prevent thermal runaway and performance degradation due to heat generation of the battery modules. [Means for solving the problem]

[0008] As one embodiment of the present invention, the present invention provides a battery pack including: a first battery module including a plurality of first battery cells; a second battery module including a plurality of second battery cells; a pack housing including an accommodating portion in which both the first battery module and the second battery module are accommodated; a partition portion forming an inner wall of the accommodating portion; and a pack BMS (Battery Management System) that controls the usable capacity of the first battery module and the usable capacity of the second battery module so that they are the same or similar, wherein the second battery module is capable of cooling the first battery module.

[0009] Also, the first battery cell may generate more heat per unit volume than the second battery cell.

[0010] The first battery module further includes a first reference cell including a first reference electrode in the first battery cell, and the pack BMS is capable of measuring a first reference potential difference of the first reference cell and a first potential difference of the first battery cell.

[0011] The first reference cell also includes a first working electrode corresponding to the positive electrode, a first counter electrode corresponding to the negative electrode, and the first reference electrode, and the pack BMS is capable of calculating the first reference potential difference based on the potential difference between the first reference electrode and the first working electrode and the potential difference between the first reference electrode and the first counter electrode.

[0012] In addition, the pack BMS can estimate the available capacity of the first battery module based on the deviation between a first reference potential difference and the first potential difference.

[0013] The first battery module further includes a second reference cell including a second reference electrode in the second battery cell, and the pack BMS is capable of measuring a second reference potential difference of the second reference cell and a second potential difference of the second battery cell.

[0014] The second reference cell also includes a second working electrode corresponding to the positive electrode, a second counter electrode corresponding to the negative electrode, and a second reference electrode, and the pack BMS is capable of calculating the second reference potential difference from the potential difference between the second reference electrode and the second working electrode and the potential difference between the second reference electrode and the second counter electrode.

[0015] In addition, the pack BMS can estimate the available capacity of the second battery module based on the deviation between a second reference potential difference and the second potential difference.

[0016] The first battery cell is a battery cell whose positive electrode active material includes nickel, cobalt, and manganese materials, and the second battery cell is a battery cell whose positive electrode active material can include lithium, phosphate, and iron materials.

[0017] Also, the second battery cell may be a battery cell in which the positive electrode active material does not contain nickel material.

[0018] In addition, the first battery module and the second battery module housed in the housing portion may be arranged such that opposing surfaces thereof are in contact with each other.

[0019] In addition, the first battery module and the second battery module may have a thermally conductive compound applied to their contacting surfaces.

[0020] The first battery module and the second battery module may include a heat dissipation material on their contact surfaces.

[0021] The heat dissipating material may be ceramic or synthetic resin.

[0022] The housing portion may house a pair of the first battery module and the second battery module.

[0023] Furthermore, a plurality of the storage sections may be provided, and the partition wall may partition the plurality of storage sections.

[0024] The partition wall may be made of a heat insulating material.

[0025] The partition wall may include a first partition wall unit arranged parallel to the longitudinal direction of the first or second battery module, and a second partition wall unit arranged perpendicular to the first partition wall unit.

[0026] The first battery module and the second battery module, which are disposed in different receiving portions facing each other with the partition wall at the center, may be disposed to face each other. [Effects of the Invention]

[0027] By accommodating a first battery module and a second battery module, each containing different types of battery cells, in a single space, the present invention can cool the battery modules through heat exchange with each other, and control the usable capacities of the first battery module and the second battery module to maintain the same or similar levels, thereby preventing thermal runaway and performance degradation due to heat generation in the battery modules. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a diagram showing a schematic plan view of a structure of a battery pack according to one embodiment of the present invention; [Figure 2] 1A is a plan view showing a first battery cell, FIG. 1B is a plan view showing a first reference cell, FIG. 1C is a plan view showing a second battery cell, and FIG. 1D is a plan view showing a second reference cell according to one embodiment of the present invention. [Figure 3] 1 is a block diagram illustrating a battery pack according to one embodiment of the present invention. [Figure 4] 1 is a block diagram illustrating a pack BMS according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0030] The present invention will now be described in detail with reference to the accompanying drawings, in which:

[0031] A preferred embodiment of the present invention will be described in detail so that those skilled in the art can easily implement the present invention; however, the present invention may be embodied in various different forms and should not be construed as being limited to the following embodiments.

[0030] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related known technologies that may obscure the gist of the present invention are omitted, and when referring to components in each drawing in this specification, the same or similar reference symbols are used throughout the specification to refer to the same or similar components.

[0031] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best explain their invention.

[0032] Referring to FIG. 1, one embodiment of the present invention relates to a battery pack 10 including heterogeneous battery cells, and the battery pack 10 may include a first battery module 100, a second battery module 200, a pack housing 300, and a pack BMS.

[0033] The first battery module 100 may include a plurality of first battery cells 110. The plurality of first battery cells 110 may be stacked and arranged in the internal space of the first battery module 100.

[0034] The second battery module 200 may include a plurality of second battery cells 210. The plurality of second battery cells may be stacked and arranged in the internal space of the second battery module 200.

[0035] The first battery cell 110 and the second battery cell may be provided in various shapes such as a pouch shape, a square shape, a cylindrical shape, or the like.

[0036] 2(a), the first battery cell 110 may include a first electrode assembly, a first pouch case 113, a first positive electrode lead 111, and a first negative electrode lead 112. The first positive electrode lead 111 and the first negative electrode lead 112 may be formed to protrude outward from the first pouch case 113, and the first positive electrode lead 111 and the first negative electrode lead 112 may protrude together from one side of the first pouch case 113 or may protrude from one side and the other side, respectively.

[0037] The first electrode assembly may have a structure in which a positive electrode current collector / positive electrode active material layer / separator / negative electrode active material layer / negative electrode current collector are stacked in this order. The positive electrode current collector includes a region coated with a positive electrode active material layer and an uncoated positive electrode uncoated region, and the positive electrode uncoated region may function as a positive electrode tab. The negative electrode current collector includes a region coated with a negative electrode active material layer and an uncoated negative electrode uncoated region, and the negative electrode uncoated region may function as a negative electrode tab. The separator is disposed between the positive electrode current collector and the negative electrode current collector to prevent contact between the current collectors of opposite polarities. One end of the first positive electrode lead 111 may be connected to the positive electrode tab, and one end of the first negative electrode lead 112 may be connected to the negative electrode tab.

[0038] 2(c), the second battery cell 210, like the first battery cell 110, can include a second electrode assembly, a second pouch case 213, a second positive electrode lead 211, and a second negative electrode lead 212. The description regarding this is the same as that for the first battery cell 110.

[0039] The first battery cell 110 and the second battery cell can be distinguished according to the positive electrode active material coated on the positive electrode current collector.

[0040] The positive electrode active material of the first battery cell 110 may be an NCM positive electrode active material containing nickel, cobalt, and manganese, an NCA positive electrode active material containing nickel, cobalt, and aluminum, or an NCMA positive electrode active material containing nickel (Ni), cobalt (Co), manganese (Mg), and aluminum (Al). In particular, the higher the nickel content in the positive electrode active material, the higher the energy density of the battery cell that can be manufactured, and nickel may account for 60% or more of the positive electrode active material.

[0041] The positive electrode active material of the second battery cell may be an LFP positive electrode active material including lithium (Li), phosphate (H3PO4), and iron (Fe) components, and may be free of nickel components.

[0042] The first battery cell 110 containing nickel as a positive electrode active material may generate more heat per unit volume than the second battery cell 210.

[0043] The first battery module 100 may further include a first reference cell 120.

[0044] 2(b), the first reference cell 120 may be a cell having a greater number of electrodes than the first battery cell 110. The first reference cell 120 may be, but is not limited to, for example, the first battery cell 110 may further include a first reference electrode 123.

[0045] The first reference cell 120 may include a first working electrode 121 corresponding to the positive electrode, a first counter electrode 122 corresponding to the negative electrode, and a first reference electrode 123 .

[0046] The first reference cell 120 may be coupled to the first battery module 100 and configured to accurately estimate the potential difference of the first battery cell 110. Because the first battery cell 110 has a two-electrode structure including a negative electrode and a positive electrode, measuring the potential difference may result in an error in the potential difference due to the resistance of the electrolyte. In the first reference cell 120, a current flows between the first working electrode 121 and the first counter electrode 122, and almost no current flows through the first reference electrode 123. Therefore, the potential of the first reference electrode 123 hardly changes, and the first reference electrode 123 may serve as a reference when calculating the first reference potential difference of the first reference cell 120. Here, the first reference potential difference may be accurately measured regardless of the current value between the first working electrode 121 and the first counter electrode 122.

[0047] The first reference potential difference can be calculated by measuring the relative potential values ​​of first working electrode 121 and first counter electrode 122 with first reference electrode 123 as a reference. More specifically, the first reference potential difference can be calculated by adding together the difference between first working electrode 121 and first reference electrode 123 and the difference between first reference electrode 123 and first counter electrode 122.

[0048] The second battery module 200 may further include a second reference cell 220. The second reference cell 220 may be a cell having a greater number of electrodes than the second battery cell 210. The second reference cell 220 may further include, for example, a second reference electrode 223 in addition to the second battery cell 210, but is not limited thereto.

[0049] 2(d), the second reference cell 220 may be coupled to the second battery module 200 and configured to estimate an accurate value of the potential difference of the second battery cell. Similar to the first reference cell 120, the second reference cell 220 may include a second working electrode 221 corresponding to the positive electrode, a second counter electrode 222 corresponding to the negative electrode, and a second reference electrode 223.

[0050] Like the first battery cell 110, the second battery cell 210 has a two-electrode structure with a negative electrode and a positive electrode. Therefore, when measuring a potential difference, an error in the potential difference may occur due to the resistance of the electrolyte. In the second reference cell 220, a current flows between the second working electrode 221 and the second counter electrode 222, and almost no current flows through the second reference electrode 223. Therefore, the potential of the second reference electrode 223 hardly changes, and the second reference electrode 223 can be used as a reference when calculating a second reference potential difference of the second reference cell 220. Here, the second reference potential difference can be accurately measured regardless of the current value between the second working electrode 221 and the second counter electrode 222.

[0051] The second reference potential difference can be calculated by measuring the relative potential values ​​of second working electrode 221 and second counter electrode 222 with second reference electrode 223 as a reference. More specifically, the second reference potential difference can be calculated by adding together the difference between second working electrode 221 and second reference electrode 223 and the difference between second reference electrode 223 and second counter electrode 222.

[0052] The pack housing 300 may refer to a frame that forms the outer shape of the battery pack 10 .

[0053] The pack housing 300 may include a container portion 310 and a partition portion 320 .

[0054] The receiving portion 310 may provide a space in the interior space of the pack housing 300 in which the first battery module 100 and the second battery module 200 are both received.

[0055] The receiving portion 310 may have an inner wall formed by the partition portion 320 .

[0056] A plurality of receiving portions 310 may be formed in the pack housing 300. The plurality of receiving portions 310 may be separated by partition walls 320.

[0057] The plurality of receiving portions 310 may be arranged in the pack housing 300 in a plurality of columns and a plurality of rows.

[0058] The partition section 320 may include a first partition unit 321 and a second partition unit 322 .

[0059] The first partition wall unit 321 is arranged parallel to the longitudinal direction of the first or second battery module, and can separate the adjacent receiving portions 310.

[0060] The second partition wall unit 322 is disposed in a direction perpendicular to the first partition wall unit 321 and can separate adjacent storage sections 310 from each other.

[0061] The partition wall 320 may be formed of a heat insulating material. More specifically, the first partition wall unit 321 and the second partition wall unit 322 may be formed of a heat insulating material. The partition wall 320 may be formed of a heat insulating material to prevent heat transfer between the battery modules 100 and 200 arranged in different receiving portions 310. This allows heat to be transferred between the pair of first and second battery modules 100 and 200 accommodated in the receiving portion 310. In particular, the second battery module 200 generates almost no heat even during use, such as charging and discharging of the second battery cells 210, and therefore can cool the first battery module 100.

[0062] A pair of the first battery module 100 and the second battery module 200 accommodated in one accommodation portion 310 are arranged so that their opposing surfaces are in contact with each other, thereby enabling active heat transfer to occur between the first battery module 100 and the second battery module 200.

[0063] In one embodiment of the present invention, the first battery module 100 and the second battery module 200 may be coated with a thermally conductive compound that improves heat transfer efficiency at the contacting surfaces and adheres the first battery module 100 and the second battery module 200 to each other. The thermally conductive compound may be, but is not limited to, a thermoplastic resin such as polyamide, polyphenylene sulfide (PPS), polyolefin, polyacetal, polycarbonate (PC), polyoxymethylene (POM), polystyrene (PS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester, liquid crystal polyester (LCP), ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene (ABS), polysulfone, polyimide, or fluororesin; a thermosetting resin such as epoxy resin, thermosetting polyimide, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, silicone resin, or thermosetting urethane resin; or a combination thereof.

[0064] In another embodiment of the present invention, the surfaces where the first battery module 100 and the second battery module 200 contact each other may be formed including a heat dissipation material with high thermal conductivity. The heat dissipation material may be, for example, a ceramic or synthetic resin material, but is not limited thereto.

[0065] In yet another embodiment of the present invention, grooves and protrusions may be formed in corresponding shapes on the surfaces where the first battery module 100 and the second battery module 200 contact each other, so as to increase the contact area.

[0066] Referring to FIG. 3, the pack BMS (Battery Management System) 400 is coupled to the pack housing and can monitor the voltage, current, temperature, available capacity, etc. of each of the first battery cell 110, the second battery cell 210, the first reference cell 120, and the second reference cell 220 included in the first battery module 100 and the second battery module 200, and can control and manage the battery cells 110, 210 to prevent overcharging and over-discharging, etc.

[0067] Referring to FIG. 4, the pack BMS 400 may include a measurement unit 410, a calculation unit 420, and a control unit 430.

[0068] The measurement unit 410 may measure a first potential difference of the first battery cell 110, a first reference potential difference of the first reference cell 120, a second potential difference of the second battery cell 210, and a second reference potential difference of the second reference cell 220.

[0069] The measuring unit 410 measures the voltage of the first positive electrode lead 111 and the voltage of the first negative electrode lead 112 of the first battery cell 110, and the calculating unit 420 calculates a voltage corresponding to the difference between the measured voltages to measure the first potential difference.

[0070] The measuring unit 410 can measure the voltage of the first working electrode 121, the voltage of the first counter electrode 122, and the voltage of the first reference electrode 123 of the first reference cell 120. The calculating unit 420 can calculate a voltage corresponding to the difference between the voltage of the first working electrode 121 and the voltage of the first reference electrode 123, calculate a voltage corresponding to the difference between the voltage of the first reference electrode 123 and the voltage of the first counter electrode 122, and measure a first reference potential difference by summing the calculated voltages.

[0071] The calculation unit 420 may calculate a deviation between the calculated first reference potential difference and the first potential difference. After calculating the deviation, the calculation unit 420 may calculate an estimated value of the usable capacity of the first battery module 100 including the plurality of first battery cells 110 using a predetermined calculation method.

[0072] The measuring unit 410 measures the voltage of the second positive electrode lead 211 and the voltage of the second negative electrode lead 212 of the second battery cell 210, and the calculating unit 420 calculates a voltage corresponding to the difference between the measured voltages to measure the second potential difference.

[0073] The measuring unit 410 can measure the voltage of the second working electrode 221, the voltage of the second counter electrode 222, and the voltage of the second reference electrode 223 of the second reference cell 220. The calculating unit 420 can calculate a voltage corresponding to the difference between the voltage of the second working electrode 221 and the voltage of the second reference electrode 223, calculate a voltage corresponding to the difference between the voltage of the second reference electrode 223 and the voltage of the second counter electrode 222, and measure a second reference potential difference by summing the calculated voltages.

[0074] The calculation unit 420 may calculate a deviation between the calculated second reference potential difference and the second potential difference. When the deviation is calculated, the calculation unit 420 may calculate an estimated value of the usable capacity of the second battery module 200 including the plurality of second battery cells 210 using a predetermined calculation method.

[0075] The pack BMS 400 can control the usable capacity of the first battery module 100 so that it is equal to or similar to the usable capacity of the second battery module 200. More specifically, the control unit 430 can control the usable capacity of the first battery module 100 so that it is equal to or similar to the usable capacity of the second battery module 200. This allows safe control to prevent runaway heat generation of the first battery module 100, which generates more heat than the second battery module 200.

[0076] The control unit 430 can predict the degree of deterioration, replacement time, and lifespan of the battery cells based on the estimated values ​​of the available capacities of the first battery module 100 and the second battery module 200.

[0077] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the scope of the claims set forth below by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0078] 10 Battery pack 100 First Battery Module 110 First battery cell 111 First positive lead 112 First negative electrode lead 113 First Pouch Case 120 First Reference Cell 121 1st working electrode 122 First counter electrode 123 1st reference electrode 200 Second Battery Module 210 Second battery cell 211 Second positive lead 212 Second negative electrode lead 213 Second Pouch Case 220 Second Reference Cell 221 2nd working electrode 222 Second counter electrode 223 Second reference electrode 300 pack housing 310 Storage unit 320 Bulkhead section 321 No. 1 Bulkhead Unit 322 Second bulkhead unit 400 Pack BMS 410 Measuring part 420 Arithmetic section 430 Control Unit

Claims

1. a first battery module including a plurality of first battery cells; a second battery module including a plurality of second battery cells; a pack housing including a receiving portion in which the first battery module and the second battery module are both received; a pack BMS (Battery Management System) that controls the usable capacity of the first battery module to be equal to the usable capacity of the second battery module; The second battery module is capable of cooling the first battery module.

2. The battery pack of claim 1 , wherein the first battery cell generates more heat per unit volume than the second battery cell.

3. The first battery module is The first battery cell further includes a first reference cell including a first reference electrode; The battery pack of claim 1 , wherein the pack BMS is capable of measuring a first reference potential difference of the first reference cell and a first potential difference of the first battery cell.

4. the first reference cell includes a first working electrode corresponding to a positive electrode, a first counter electrode corresponding to a negative electrode, and the first reference electrode; 4. The battery pack according to claim 3, wherein the pack BMS is capable of calculating the first reference potential difference from a potential difference between the first reference electrode and the first working electrode and a potential difference between the first reference electrode and the first counter electrode.

5. The battery pack according to claim 4 , wherein the pack BMS estimates a usable capacity of the first battery module based on a deviation between the first reference potential difference and the first potential difference.

6. The first battery module is The second battery cell further includes a second reference cell including a second reference electrode; The battery pack of claim 5 , wherein the pack BMS is capable of measuring a second reference potential difference of the second reference cell and a second potential difference of the second battery cell.

7. the second reference cell includes a second working electrode corresponding to the positive electrode, a second counter electrode corresponding to the negative electrode, and a second reference electrode; 7. The battery pack according to claim 6, wherein the pack BMS is capable of calculating the second reference potential difference from a potential difference between the second reference electrode and the second working electrode and a potential difference between the second reference electrode and the second counter electrode.

8. The battery pack according to claim 7 , wherein the pack BMS estimates a usable capacity of the second battery module based on a deviation between the second reference potential difference and the second potential difference.

9. The first battery cell is a battery cell in which a positive electrode active material includes nickel, cobalt, and manganese materials, The battery pack according to claim 1 , wherein the second battery cell is a battery cell whose positive electrode active material includes lithium, phosphoric acid, and iron material.

10. The battery pack according to claim 9 , wherein the second battery cell is a battery cell whose positive electrode active material does not contain nickel material.

11. The battery pack according to claim 1 , wherein the first battery module and the second battery module housed in the housing portion have opposing surfaces in contact with each other.

12. The battery pack according to claim 11 , wherein the first battery module and the second battery module have a thermally conductive compound applied to their contacting surfaces.

13. The battery pack according to claim 11 , wherein the first battery module and the second battery module include a heat dissipation material on their contacting surfaces.

14. The battery pack according to claim 13 , wherein the heat dissipation material is ceramic or synthetic resin.

15. The battery pack according to claim 1 , wherein the housing section houses a pair of the first battery module and the second battery module.

16. The container further includes a partition wall portion that forms an inner wall of the container portion, The battery pack according to claim 15, wherein a plurality of the storage sections are provided, and the partition wall defines a partition between the plurality of storage sections.

17. The battery pack according to claim 16, wherein the partition wall is formed of a heat insulating material.

18. The partition wall is a first partition wall unit arranged parallel to a longitudinal direction of the first or second battery module; 17. The battery pack according to claim 16, further comprising: a second partition unit disposed in a direction perpendicular to the first partition unit.

19. The battery pack according to claim 16 , wherein the first battery module and the second battery module, which are disposed in different housing portions facing each other with the partition portion as the center, are disposed to face each other.

Images